Low water solubility compositions for use in corrosion protection

ABSTRACT

The invention relates to compositions, methods and preparation of such compositions to protect metals from corrosion, especially acid corrosion. The compositions of this invention may be added to acids to protect metals from their corrosive influence, particularly at elevated temperatures. These compositions are of particular utility in the oil and gas (petroleum) industry. Also disclosed are “corrosion inhibition intensifiers” to enhance the corrosion inhibition properties of other corrosion inhibitors. Formulations which control ferric ions in acidic solutions are also disclosed. These may be combined with inhibited acids and some compositions provide both corrosion inhibition and ferric ion control.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/453,670, filed on Mar. 8, 2017 now U.S. Pat. No. 10,072,339,which is a continuation of U.S. patent application Ser. No. 14/701,001,filed on Apr. 30, 2015, now abandoned, which claims priority to the U.S.provisional application Ser. No. 61/987,477, filed on May 1, 2014, andalso U.S. provisional application Ser. No. 62/035,388, filed on Aug. 9,2014. This application is a continuation-in-part of U.S. patentapplication Ser. No. 14/843,556, filed on Sep. 2, 2015, which is acontinuation of U.S. patent application Ser. No. 14/089,146, filed onNov. 25, 2013, now patented as U.S. Pat. No. 9,155,310, issued on Oct.13, 2015, which claims priority to U.S. provisional application Ser. No.61/881,318, filed on Sep. 23, 2013. The contents of all of the foregoingapplications are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The invention relates to corrosion inhibitor compositions, methods andpreparation of these compositions to protect metals from corrosion,especially acid corrosion. This is of particular interest in the oil andgas (petroleum) industry, but also has application in other industries.The compositions of this invention may be added to acids to protectmetals from the corrosive influence of these acids. These may also beused as “corrosion inhibition intensifiers” to enhance the corrosioninhibition properties of other corrosion inhibitors. Collectivelycorrosion inhibition and corrosion inhibition intensification will becalled “corrosion inhibition” unless called out separately.

BACKGROUND OF THE INVENTION

Corrosion of metals in contact with acids is caused by reaction betweenthem. In many industrial processes and equipment (e.g., piping, tanks,valves, cooling towers, heat exchangers, etc), acids (or aqueous acidicsolutions, collectively called “acids”) are used for periodic cleaningof metallic components (e.g., removing of deposited scale); and suchexposure to acids causes enhanced corrosion of the metals. Sometimescorrosion inhibitors are also added to water to reduce corrosion causedby its reaction with metals. In some industrial applications such as oilwells, one may use strongly corrosive acids for cleaning well bores,particularly for newly installed wells and also for periodic stimulationof existing wells to restore production rates of oil and gas.Acidization or acid treatments of oil and gas wells is also done as partof fracking process, where typically the acidization treatment isfollowed by injecting large volume of water and sand particles withother components under pressure. This stimulation is done to dissolvedebris-blocking porosity and cracks in rock formations which block theflow of oil or gas. Since the addition of these acids in the wells isdone through metallic (mainly ferrous) pipes, the acids can corrodethem. In the petroleum industry, corrosion problems (reaction betweenacid and metals) intensify with depth of the wells, as the temperatureincreases with depth. In some cases, acids can come in contact metals atelevated temperatures in a range from about 60° C. to about 250° C.under high pressure and rapid flow conditions. Although the protectionof ferrous metals is an important focus; the present invention may alsobe used in protecting other metals and alloys from corrosion, especiallyacid corrosion. Since corrosion accelerates under elevated temperaturesand in the presence of strongly corrosive acids, corrosion inhibition ofmetals under these conditions becomes more important.

The corrosion inhibition being addressed here is different from thecorrosion caused or increased by microbes (such as sulfate reducinganaerobic bacteria), where for example iron may be converted to softiron sulfide. Such corrosion protection is achieved by killing thebacteria and or protecting metals from the gases released by suchbacteria. In this invention the main issue being addressed is acidcaused corrosion rather than microbially-induced corrosion (MIC). Thepurpose of the present invention is to reduce corrosion by preventingreaction between acids and metals by incorporating additives of thepresent invention in the acidic fluids. Strongly corrosive acids aregenerally pumped down oil wells in so called acidification treatmentswhich are the focus of the present invention, while the biocides used tokill microbes are usually incorporated in aqueous solutions without suchacids.

The extent of corrosion is typically expressed in terms of the weightloss/area (as kilograms of reduction in metal weight due to corrosionfor each square meter of exposed area or pounds/sq ft, etc.) in aspecified period of time. In some cases corrosion is also expressed interms of reduction in the number of corrosion pits (when pittingcorrosion takes place). When corrosion is measured on samples ofidentical geometry then it may also be expressed as % weight loss forrelative comparison. The focus of this disclosure is on additives foraqueous acidic solutions so that corrosion of a metallic component isdecreased when they are put in contact with acids. Typically higherconcentrations of the corrosion protection agent will be required toachieve a desired level of corrosion inhibition with increasing acidstrength and temperature. In some cases, the corrosion inhibitors ofthis invention may also be added to other petroleum well completion andproduction fluids.

Important processing steps in the petroleum industry where acids aretypically added include:

-   -   1. Drilling, completion and workover fluids.    -   2. Cleaning of well bores (e.g., newly cemented wells)    -   3. Hydraulic fracturing (fracking) process.    -   4. Flooding and injecting of water during production of oil and        gas.    -   5. Pipelines, tank flush, pipeline pigging and scraping and        packer fluids (maintenance).    -   6. Well stimulation        Among these processing operations, strong acids are commonly        used for cleaning well bores, fracking and well stimulation. The        strong acids dissolve cement residues from well bores and in        fracking and stimulation they dissolve constituents of        underground formations to increase the porosity of these        formations in order to enhance oil flow and recovery.

Some of the ferrous metals used in the petroleum industry for whichcorrosion protection is desired are chrome steels, low carbon steels,duplex steels, stainless steels, martensitic alloy steels, ferriticalloy steels, austenitic stainless steels, precipitation-hardenedstainless steels, high nickel content steels, etc. Some of the specificalloys routinely used in the petroleum industry for tubing and pipingapplications include N-80, L-80, J-55 P-110, 13Cr (regular, modified andsuper-chrome), 22Cr, QT800, QT900 and QT 1000, etc. To protect thein-place tubes cemented to the well bores and to reduce the amount ofacid needed, one lowers a flexible tubing (coiled in a spool, and calledcoil tubing) into the well bore close to the bottom so that acid can bedelivered through this tubing. These coil tubings are typically made oflow carbon steel and may corrode with repeated acid use. Such tubes alsoneed protection from the acids to prolong their lives. Some examples oftypical acidic compositions used in the petroleum industry are:

-   -   1. Hydrochloric acid in a range of 5 to 34% strength by weight.    -   2. Acetic acid in a range of 1 to 15% strength by weight.    -   3. Formic acid in a range of 1 to 10% strength by weight.    -   4. Hydrofluoric acid in a range of 0.5 to 6% strength by weight.    -   5. Mixtures of these acids in such concentrations.

It is well known that hydrochloric acid, acetic acid and formic acid arewidely used in carbonate formations, while mixtures of hydrochloric acidand hydrofluoric acid are used in sandstone formations (e.g., 3% HF+12%HCl). For purposes of the present application, acids such as thoselisted in 1-5 are referred to as strongly corrosive acids. In the caseof acetic acid and formic acid, these acids qualify as stronglycorrosive when they encounter temperatures such as 90° C. to 250° C. incertain subteranian formations or used in mixtures with the other acidslisted above.

The acids are selected based on well characteristics such as the tubularsteel compositions and the geology of the rocks. The acids are mixedwith corrosion inhibitors and other additives before they are injectedinto the wells. Some examples of these additives are iron control agents(e.g., citric acid, acetic acid), breaker materials (e.g., NaCl, CaCl₂),scale inhibitors (sodium polycarboxylate, phosphonic acid salt),surfactants (nonionic, cationic and anionic), reducing agents (sodiumerythorborate, thio compounds) and viscosity modifiers. All of theadditive components should be selected so that they are mutuallycompatible when added to the acids.

The corrosion inhibitors/intensifiers of this invention may be combinedwith additional corrosion inhibitors (including conventional corrosioninhibitors) or corrosion inhibition intensifiers (CIIs). One aspect ofthis innovation is the use of solid corrosion inhibitor or CIIcomponents which have low water solubility. A highly preferred method ofadding such materials according to the present invention involvespreparing surface functionalized particles which can easily be dispersedin aqueous media. Low water solubility materials are defined as thosewhich at room temperature have a water solubility of less than 100mg/liter and preferably less than 15 mg/liter of water. The surfacefunctionalization is typically carried out using materials which have amolecular weight of at least 60 and prefereably at least 80 and mostpreferably at least 100. More on surface functionalization andpreparation of such particles is provided in published US patentapplication 2014/0271757 the disclosure of which is included herein byreference. Corrosion inhibitor formulations which combine severalinhibitors synergistically is also an object of the present invention,as are corrosion inhibitors that reduce ferric ions to mitigate thecorrosion caused by such ions and also to mitigate sludge formationcaused by ferric ions.

SUMMARY OF THE INVENTION

The corrosion inhibitors or corrosion inhibition intensifiers of thisinvention may be added to acidic solutions in order to reduce thecorrosion of metals (or the reactivity with metals) which come incontact with such acidic solutions. Typical temperature range ofinterest in which acids contact the ferrous metals and alloys in thepetroleum industry is from about ambient temperature to about 230° C.Corrosion caused by acids is more severe when the metal-acid contacttakes place at higher temperatures. Strongly corrosive acids are used inoil wells for cleaning well bores, fracking and also to stimulate themwhen their output decreases. One aspect of this invention is to be ableto use effectively low water solubility additives which when added toacids reduce their corrosive effects on metals. Another aspect of thisinvention is to provide corrosion reduction additives. Yet anotheraspect of this innovation is to teach materials which eliminate/reduceferric ions which are responsible for corrosion and sludge formation.Many of the formulations made using the embodiments below may have othercomponents which may be inert or have mild inhibiting characteristics,but are added as carriers, solvents, colorants for distinguishingvarious products, etc. Some of these are water, alcohols (usually C1 toC4), glycols (e.g., polyethylene and polypropylene glycols) withmolecular weight of about less than 400, etc.

The present invention provides additive(s), and compositions (orformulations) that include the additive(s) that provide corrosioninhibiting characteristics to the type of acidic compositions that arefound in the petroleum industry, and which additives can have use incorrosion inhibiting characteristics to acidic compositions for otherindustrial applications.

In one of its basic aspects, a composition according to the presentinvention comprises an an acidic solution with a corrosion inhibitingadditive, where the corrosion inhibiting additive comprises a low watersolubility material which is dispersible in an aqueous medium asparticles whose surfaces are modified by a surface functionalizationagent with a molecular weight of at least 60.

In a more specific form of this composition, the low water solubilitymaterial comprises a cuprous salt. Moreover, the corrosion inhibitingadditive may be further combined with a material which additionallyprovides ferric ion reduction properties.

Also, the surface functionalization agent is preferably selected from atleast one of PVP, PVP copolymer, surfactant, an organic acid and a saltof an organic acid.

The corrosion inhibiting additive can comprise at least one lowsolubility surface functionalized particles of cuprous salt, and atleast one additional metal compound selected from a Cu compound which isdifferent from surface functionalized cuprous salt and compounds of ametal selected from Li, Na, K, V, Co, Mo, Ta, Sn, Bi, Mn and W.

Still further, the corrosion inhibiting additive further comprises atleast three materials selected from the following categories, wherein atleast one material is selected from each of these categories:

-   -   (a) cationic surfactant;    -   (b) phenylpropanoid, and    -   (c) and a material selected from at least one of a monomeric        material and a nitrogen containing material.

Still further, the monomer can be acetylenic; the phenylpropanoid iscinnamonaldehyde; the nitrogen containing material can be selected fromquinolines, nicotinic acid, and PVP containing polymer; and thesurfactant can be a cationic salt selected from ammonium, phosphonium,imidazolium, pyridinium, pyrrolidinium, pyridazinium, pyrimidinium,pyrazinium, imidazolium, pyrazolium, and triazolium salts containinghalide anions. More specifically, the acetylenic monomer can comprisepropargyl alcohol or its derivative, the cinnamonaldehyde can comprisetranscinnamonaldehyde, and the cationic salt has at least one alkylchain with an average length of C12 to C15. The additive can alsocontain a corrosion inhibition intensifier which comprises at least oneof a compound of V, Co, Mo, Ta, Sn, Bi, Mn, W, Cu and I. As an example,the corrosion inhibition intensifier can be selected from CuI, LiI, KIand NaI. The acidic compositions containing these corrosion inhibitorsmay also contain additives which reduce ferric ion species.

As applied specifically for acids used in the petroleum industry, aniron control formulation is provided for reducing ferric ion species inan acidic solution employed in the petroleum industry, the formulationcomprising a reducing agent and a cuprous compound selected from atleast one of cuprous halides, cuprous oxide and cuprous acetate.Preferably, the cuprous halide is copper iodide, the cuprous compound isadded as particles whose surfaces are modified by a functionalizingagent, and the reducing agent is a non-sulfur containing material.

Additives that provide both corrosion inhibition and reduction of ferricions comprise at least four materials, selected from:

-   -   (a) cationic surfactant;    -   (b) at least one of a monomeric material, a nitrogen containing        material.phenylpropanoid;    -   (c) a reducing agent; and    -   (d) cuprous/transition metal salts

The above additive package may also comprise an additional iodinecontaining compound. In the above additive package, preferably themonomer can be acetylenic; the phenylpropanoid is cinnamonaldehyde; thenitrogen containing material can be selected from quinolines, nicotinicacid, and PVP containing polymer; and the cationic surfactant can be asalt selected from ammonium, phosphonium, imidazolium, pyridinium,pyrrolidinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium,pyrazolium, and triazolium salts containing halide anions. Preferredreducing agents do not comprise sulfer and a preferred cuprous compoundis CuI.

The corrosion inhibitors/intensifiers of this invention may be combinedwith additional corrosion inhibitors (including conventional corrosioninhibitors) or corrosion inhibition intensifiers (CIIs). One aspect ofthis innovation is the use of dispersible particles of solid corrosioninhibitor or CII components which have low water solubility. A highlypreferred method of adding such materials according to the presentinvention involves preparing surface functionalized particles which caneasily be dispersed in aqueous media. Low water solubility materials aredefined as those which at room temperature have a water solubility ofless than 100 mg/liter and preferably less than 15 mg/liter of water.The surface functionalization is typically carried out using materialswhich have a molecular weight of at least 60 and prefereably at least 80and most preferably at least 100. More on surface functionalization andpreparation of such particles is provided in published US patentapplication 2014/0271757 the disclosure of which is included herein byreference. Corrosion inhibitor formulations which combine severalinhibitors synergistically is also an object of the present invention,as are corrosion inhibitors that reduce ferric ions to mitigate thecorrosion caused by such ions and also to mitigate sludge formationcaused by ferric ions.

Some Exemplary embodiments of the present invention are described below.

Embodiment 1

This embodiment is directed to the use of particles of low watersolubility metal salts which provide good corrosion inhibition. This isdone by producing particles of these materials wherein the surfaces ofthe particles are modified (functionalized particles) so that these maybe dispersed uniformly in acidic media. Preferably these particles arepre-formed prior to their addition to the acids. A preferred range ofsize of such particles is between 3 and 1,000 nm, more preferablybetween 50 and 500 nm and most preferably between 100 and about 300 nm.A preferred low water solubility material for this purpose is cuprousiodide. The functionalization agents should have a molecular weight ofat least 60, preferably at least 80 and more preferably at least 100.One may use one or more than one functionalization agent. Preferredsurface functionalization agents are either water/acid compatible or arehydrophilic. Some of the preferred materials are PVP, PVP copolymers,chitosan, surfactants (ionic and nonionic), organic acids and salts oforganic acids.

Embodiment 2

In another embodiment, the corrosion inhibition formulation comprisessurface functionalized particles as corrosion inhibitor intensifiers(CII). This means that the formulation comprises other corrosioninhibitors, but CII are added to further enhance the corrosioninhibition. Typically CII are used when it is desired that the acidswill contact metals at a temperature greater than about 200° F., andpreferably once the temperatures reach 250° F. or higher. Although anycorrosion inhibitors may be used to which these CII are added. Thepreferred corrosion inhibitors comprise one or more of (a) a polymerwhich binds to iodine (b) monomers, (c) phenylpropanoids and/orcarotenoids, (d) quinolines and (e) an ionic material selected from atleast one of an organic acid, salt of an organic acid and a cationicsurfactant. Additional CII with different chemistry may also be used inthe formulation, and some of the preferred ones are water soluble metalsalts, including iodides including water soluble iodides.

Embodiment 3

In another embodiment, the corrosion inhibitor formulation combines atleast three corrosion inhibitors of which at least one is a cationicsurfactant, the second is a phenylpropoanoid and the third is selectedfrom one of a monomeric material and a nitrogen containing compound.Such formulations may comprise additional inhibitors, which may beselected from these three classes of materials or of other types. Thecorrosion reducing effects of the above formulation may be intensifiedby using metal salts such as those listed in Embodiment 2. Some of thepreferred cationic surfactants are ammonium salts with average alkylchains longer than about C8 and most preferred embodiments have averagealkyl chains of C12 to C15. The preferred phenylpropanoid iscinnamonaldehyde and preferred monomers are acetylenic monomers andpreferred nitrogen containing compounds are PVP containing polymers,quinolines and nicotinic acid. It is also preferred that the formulationcontain a higher weight percentage of the third inhibitor type (i.e.,monomeric material or a nitrogen containing compound) as compared to theother two inhibiting constituents. Any of the corrosion inhibitorintensifier (CII) as described in Embodiment 4 and/or an iodine (iodide)containing compound may be used to improve or intensify the corrosioninhibition of the formulations of this embodiment.

Embodiment 4

In yet another embodiment, the corrosion inhibitor formulation comprisesat least two CIIs. The first of these two CII comprise a cuprous salt,and the second CII comprises a metal compound (including metal salts)where at least one metal is selected from Li, Na, K, V, Co, Mo, Ta, Sn,Bi, Mn, W and a Cu compound which is different from the first CII.Iodides of alkali metals are preferred as the second CII.

Embodiment 5

This embodiment relates to formulations to be used with acids (usuallystrongly corrosive acids) for reduction or control of ferric ions by useof cuprous compounds in these formulations. These formulations may bemade only for ferric ion control, or both for ferric ion control andreduction of corrosion due to acid/metal reaction. Water insolublecuprous compounds can be used as surface functionalized particles. Useof cuprous compounds results in highly effective ferric controlformulations. Preferred cuprous compounds are cuprous halides, cuprousoxide and cuprous acetate. Of these a more preferred compound is CuI.The reduction of ferric ions leads to the mitigation of ferric ioncorrosion and/or reduction of sludge caused by ferric ions. Thisembodiment also envisages the use of cuprous compounds such as CuI bothas a generic corrosion inhibitor (Embodiment 1) or corrosion inhibitorintensifier (CII) (Embodiment 2) along with at least one reducing agentso that these formulations work for their intended purpose as laid outin Embodiments 1 and 2, while also providing ferric ion control. Some ofthe reducing agents are sulfites, thiosulfates, thioglycolates, ascorbicacid, sodium ascorbate, erythorbic acid and sodium erythorbate. Thepreferred reducing agents are non-sulfur containing materials. Inanother variation any ferric ion reducing composition may be added tothe corrosion inhibitors of Embodiment 3 to result in those compositionswhich result both in effective ferric ion reduction and also in superiorcorrosion protection of metallic materials against acidic corrosion.

Embodiment 6

In this Embodiment, formulations which provide Ferric ion control inacidic solutions comprise metal compounds containing multivalenttransition metals, preferably selected from V, Co, Mo, Ta, Sn, Bi, Mnand W, together with a source of iodine and a reducing agent. Theselection of the reducing agents is the same as in Embodiment 5. Atleast a portion of iodine can be provided by the metal compound.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Shows uniform dispersion of an inventive formulation comprisingsurface functionalized particles of CuI vs settling of bulk copperiodide in 15% HCl;

FIG. 2: Optical transmission showing reduction kinetics of ferric ionsusing various compositions.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Corrosion of metals is an important industrial issue, particularly whenferrous metals and alloys contact acids. Strongly corrosive acidicsolutions are used for cleaning, industrial processes, and in thepetroleum industry. Corrosion becomes more severe when the acid contactsmetals at elevated temperatures; and it is not uncommon for deeppetroleum wells to have temperatures as high as 230° C. or even higher.

It is preferred that the corrosion inhibition additive comprising thevarious constituents described above be added to treatment acids inconcentrations of less than about 5% (i.e., 50,000 ppm), preferably lessthan about 2% and most preferably less than about 0.5% (all by weight).The concentration (and the ratio of the constituents amongst themselves)is dependent on the corrosiveness of the liquid being used, the type ofmetal being protected, the temperature at which the interaction willhappen, and also the duration for which the corrosion protection isbeing sought. Since the addition of these components increases cost andsome of these may have toxicity issues at large concentrations, it isalways desired that the additive concentration for a given task shouldbe as small as possible as long as it attains its objective. The chartbelow shows an approximate guideline for desirable concentration limitsof corrosion inhibitors used in strongly corrosive acids (e.g., 15% HCl)as a function of maximum temperature at which the acids and the metalsinteract.

Preferred More Preferred Maximum concentration Maximum of entirecorrosion Temperature, ° C. inhibition package, ppm 100 6,000 3,000 15010,000 5,000 200 20,000 10,000 >200 50,000 15,000

U.S. Pat. No. 3,773,465 teaches the use of cuprous iodide along withknown corrosion inhibitors to reduce corrosive aspects of hydrochloricacid (such as 5 to 34% HCl) solutions on ferrous metals and alloys.These acids are used to stimulate petroleum wells, and function bydissolving sediments and deposits blocking the porosity in rocks so thatthe well production can be restored. As the wells become deeper,particularly in off-shore drilling, the temperatures increase withincreasing depth and the corrosive power of these acid solutions alsoincreases. It was taught in the above patent that cuprous iodide couldbe added or produced in situ by the reaction of a copper salt (or copperoxide) and a water soluble iodide salt such as NaI and KI. It waspreferred that there was a small excess (5 to 15%) of the water solubleiodide salt as compared to the stoichiometric amount of copper salt. Aconcentration range of 25 to 25,000 ppm of CuI was needed to reducecorrosion in a temperature range of 150° F. (about 66° C.) to 450° F.(232° C.). It was important that cuprous iodide be combined with smallmolecular weight organic compounds belonging to the class of acetylenicor a nitrogen containing compound(s) (e.g., also see U.S. Pat. No.3,514,410 for description of corrosion inhibitors using acetylenic andnitrogen compounds, wherein such list is included herein by reference).The impact of addition of CuI on corrosion was particularly noteworthywith increasing temperature. Since CuI was used with other small organicmolecules as described above, it was called as “corrosion inhibitionintensifier (CII)”. However, use of copper iodide has been difficult dueto its low water solubility, and CuI is not currently used in thisapplication, it is also recognized in a US patent application2009/0156432 that as CII, cuprous iodide, is effective at hightemperatures to up to about 350° F.

US published patent application 2011/0100630 teaches that the use ofalready-formed cuprous iodide is problematic and teaches a method ofin-situ formation of cuprous iodide. This application notes that whencuprous iodide powder is directly added to an acid, it does not havesufficient solubility to make its use practical. To overcome thisproblem, the application teaches generating cuprous iodide in situ fromthe reaction of a soluble iodide salt and a soluble copper salt mixed onthe fly at or near the wellhead. The application suggests using cupricacetate along with KI in acids to generate CuI.

When cuprous ions (e.g. introduced by using CuI or another cuprouscompound) are introduced in a corrosion inhibition formulation, thesealso work as reducing agents (to reduce ferric to ferrous ion). Ferricions (from oxidixed iron scale-rust present in pipes) cause severalproblems. First the presence of ferric ions especially when chlorideions are present (e.g., when HCl is present) enhance corrosion of steels(2Fe³⁺+Fe→3Fe²⁺) and also of many other metals and alloys. In additionto corrosion, particularly in oil and gas wells, ferric hydroxide beginsto precipitate from hydrochloric acid solution when the pH of the acidincreases to a value of about 2.5 and greater. This precipitation isserious when an acid, such as hydrochloric acid, containing dissolvedferric iron (which may be coming from rust) is used to react with asubsurface, acid soluble formation such as limestone. The acid reactionwith the limestone causes the pH of the acid solution to rise. Inaddition, high concentrations of acid, e.g., HCl about 15% and greater,can also cause the development of sludge when the acid is placed incontact with certain types of crude oil. The sludge formation isincreased when the acid which is in contact with the crude oil alsocontains ferric ions. Such precipitation and sludge formation make therecovery and the flow of oil difficult. Thus in acidization treatments,control of ferric ion is also important, for which CuI functionalizedparticles can provide both corrosion protection by reducing theacid/metal interaction and also by reduction of ferric ions. CuIprovides both, a source of cuprous and iodide ions.

U.S. Pat. No. 8,003,581 teaches use of sludge reduction by using a watersoluble cupric salt (cupric chloride), source of a water soluble iodidesalt (potassium iodide) and a sulfur compound selected from at least oneof sulfite (e.g., sodium sulfite) salt and/or a bisulfite salt (sodiumbisulfite). The present invention found that one can use cuprous saltsrather than cupric salts, and in particular cuprous iodide to substitutecompletely or in part for the sources of copper and iodide ions in theformulation described in the referenced patent and get efficient ferricreduction. It was also determined that when cuprous compounds (e.g.,cuprous salts) are used, it is not necessary to use sodium sulfite orsodium bisulfate to get rapid reduction of ferric to ferrous iron. Ifcuprous compounds are not soluble in the formulations, then thesematerials may be added as functionalized particles to obtain gooddispersion while still being effective in reducing ferric ions. In somecases if the introduction of sulfur containing reducing agents is notdesired since these compounds or their reactive products can be apotential food source for anaerobic sulfate reducing bacteria, then onemay also use non-sulfur containing reducing agents. Use of low watersolubility cuprous salts such as CuI as surface functionalized particlesprovides the capability of releasing ions for an extended period oftime, thus continually providing a source of ions for ferric reductionand providing corrosion protection. Such particles with properfunctionalization may also attach to the pipe (steel) surfaces thusproviding a protectant species at the point of corrosion and herebyenhancing their effectiveness.

Embodiment 1

Although bulk CuI powder may dissolve in or react with acidic solutionsat elevated temperatures, it is difficult to achieve good dispersionunder typical mixing conditions (from about 0° C. to 50° C.), and thereactive method to produce CuI particles in-situ is not desirable (seeUS published patent application 2011/0100630) as the reaction conditionsnear the well head may change (e.g., change in temperature during theday or with seasons), and as this mixture travels down the well, thetemperature and the pressure changes rapidly. As one embodiment of thisinnovation, it is much more preferable to use pre-formed dispersibleparticles with low solubility in aqueous solutions including acidicaqueous liquids. One way to pre-form such particles, such as of CuI, isto form particles with their surfaces functionalized so that theparticles remain suspended in the acidic fluids and remain uniformlydispersed. The size of surface functionalized particles which dispersein a liquid medium may be any as long as they remain dispersed, and apractical range is from about 3 to 1,000 nm. The size of the dispersedparticles is dependent on the viscosity of the liquid medium, the typeof functionalization used, and the difference in density between theliquid and the particles. For uniform particulate dispersion it ispreferred that the average particle size be about 1000 nm or lower, morepreferably below 300 nm and most preferably between 100 and 300 nm. Onemay also combine particles of different sizes/compositions. As anexample, one may combine particles about 300 nm in average size withthose less than 30 nm in average size, or one may combine particlesabout 1,000 nm in average size with those smaller than 200 nm in averagesize, etc. In one embodiment, the present invention teaches the use ofthose ingredients which improve corrosion inhibition, but have low waterand/or acid solubility (in a range of about 0 to 60° C.). When particlesof these ingredients are surface functionalized, they become easilydispersible in water or in the acid formulations in which they are to beused. In some instances, easily dispersed particles may also be easierto solubilize in aggressive solvents, such as acids. The corrosioninhibition formulations comprising these particles may further compriseadditional corrosion inhibitors.

The processes used to form surface functionalized particles andfunctionalization agents are well described in published US patentapplications 2014/0271757 and 2013/0315972 all of which are includedherein by reference.

Low water solubility cuprous compounds are preferred as a source ofcorrosion inhibition materials (or copper salts). These include Cu₂O,CuCl and CuI. CuI is most preferred in many cases as it provides both asource of cuprous metal ions and also iodide ions, as both of these ionsshow corrosion inhibition properties. Functionalized particles of CuOmay be used in some cases.

Another class of solids which are insoluble or have low water solubilityare materials (or salts) with more than one cation (e.g., mixed metaliodides and oxides), such as K₄BiI₇, which is an iodide salt of both analkali metal (K) and a non-alkali metal (Bi). The low water solubilitysalts may also comprise more than one non-alkali metals such as CuAgI (asolid solution of equimolar CuI and AgI), which may be writtengenerically as Cu_(x)Ag_(y)I_(z) and x+y=z represents a material whereCuI and AgI are present in any proportion. Another example isBi_(x)Mo_(y)O_(z) (a solid solution of Bi₂O₃ and MoO₃) representedgenerically by Me1_(x)Me2_(y)O_(z) where Me1 and Me2 are differentmetals.

During the production of surface functionalized particles, thefunctionalizing agents should be present while the particles or newsurfaces are being formed. The particles may be formed either bychemical synthesis, or by physical grinding from larger particles. Theamount of surface functionalizing agent increases with decreasingparticle size, there is an increase in the surface area of theparticles. While any ratio of of the metal salt particles and thefunctionalizing material may be used, a preferred weight ratio (metalsalt to functionalizing agent) in a range of about 25:1 to 1:20 and morepreferably in a range of about 20:1 to 1:2. The molecular weight of thefunctionalization agents should preferably be at least 60, morepreferably greater or equal to 80 and most preferably greater or equalto 100.

Although an important purpose of the surface functionalization agent isto prevent particles from agglomeration (e.g., promoting suspensionstability in liquid mediums), in some cases functionalization agents mayalso assist in increasing in corrosion inhibition, or help in theirattachment to the metallic surfaces which are being protected.

Functionalized particles are typically produced by synthesizing orproducing particles in a liquid media in presence of functionalizingagents. The resulting particle suspensions may subsequently be driedinto solid powders or used in the liquid state so that they can bemetered volumetrically and pumped into acidic solutions. Solid powderscan be stored and transported more compactly and at a lower cost. Thesize of such dried powder particles will in general be larger than thesize of the individual functionalized particles, as each of the dryparticles or granules will comprise several functionalized particles.The size of the dried powder particles should be greater than about 1micron, preferably greater than about 10 microns and most preferablygreater than about 100 microns. This allows downstream operations usingthe dry powders to be conducted safely without having the powderparticles become airborne. The larger particles do not get airborneeasily; and 100 micron particles are unable to penetrate thoracicairways in lungs and are safer to use in an industrial setting. Thedried powders may then be used to make corrosion inhibition products byadding them to a liquid carrier such as water and/or acids. When thesepowder particles are added to the carriers, these particles will breakdown and result in a uniform dispersion of the smaller functionalizedparticles.

The preferred surface functionalization materials are hydrophilic and/orwater compatible and these may be small molecules or polymeric. Althoughany functionalization agents may be used, some of the preferredfunctionalization agents are discussed below.

The agents which are selected should be compatible with the otheringredients used in the corrosion inhibition formulation and the acids.Some of the other additives used for corrosion inhibition formulationsare viscosity modifiers, iron control agents, sludge formationreducers—e.g., by reducing their formation, or wetting and floatingmineral particles such as sandstone and carbonates, controllers forcalcium sulfate (anhydrite) settlement, reducers of viscous formationsof acid or spent acid/oil products, etc. For greater compatibility withthese ingredients and the corrosion inhibitors one may also select oneor more of these ingredients for surface functionalization.

Some specific functionalization agents include natural polymers such asstarch, guar gum, chitosan, glycogen and protein based polymers.Synthetic polymers such as polyvinyl acetate, poly(vinyl alcohol) (PVA),polyethylimine, polyurethanes, polyacrylic/methacrylic acid,poly(vinylpyrrolidone) (PVP) and polyamides (nylons, polyacrylamides),polyimines (e.g., poly(Schiff bases), conjugated polymers such aspolyisoprene, polybutadiene, acetylenic polymers, inherently conductivepolymers such as polyaniline, polypyrrole and polythiophenes (inconducting or non conducting states), and their copolymers includingrandom, block and graft copolymers are all included, (copolymer of agiven polymer is defined as any polymer which has sequences of the givenpolymer (or prepared from monomer compositions, where such compositionscomprise monomers from which the given polymer is prepared)) and theother part of the copolymers can be any. Of these the preferredmaterials are PVP and copolymers, s (PVP copolymers means all polymerswhich have any segments of polymerized vinyl pyrrolidone). Copolymers ofPVP along with at least one of polycaprolactum, polyolefin and polyvinyl acetate are preferred. In the above list there are somehydrophobic polymers, since preferred materials are hydrophilic or watercompatible, those should be used as copolymers where the comonomers arethose which would result in water compatibility. One may also usebiodegradable polymers and copolymers such as polylactic-PLA acid andpoly glycolic acid-PGA.

Each of the above polymers may have a range of molecular weights,typically in the range of about 1,500 and 1,000,000 Daltons, althoughmolecular weights less than 200,000 are preferred, and molecular weightsless than 100,000 are most preferred. One may also combine severalfunctionalization agents, and these may be also selected from polymericand nonpolymeric materials.

The general class of organic acids for surface functionalizationincludes amino acids and salts of all these acids. Some preferredexamples of organic acids (including their salts) are acetic acid,citric acid, ascorbic acid, erythorbic acid, lactic acid, sodiumacetate, sodium citrate, sodium lactate, sodium ascorbate, sodiumerythorbate, etc. Some of the preferred amino acids are arginine,lysine, aspartic acid, glutamic acid, glutamine, glycine, alanine andleucine.

The surfactants (non ionic, anionic and cationic) along with salts oforganic acids may be used as surface functionalization agents. Thepreferred surfactants for use with metal salts are anionic and non-ionicsurfactants. As discussed later surfactants may also be used ascorrosion inhibitors, particularly cationic surfactants. However, onehas to be careful in mixing anionic and cationic surfactants together oreven using one as a surface functionalizing agent and the other as acorrosion inhibitor in the same formulation so that these do notinteract negatively and cause the system to destabilize. Sometimes thesematerials may not be compatible with each other in a formulation whichneeds to be stored and transported, but would be acceptable for this useif they both were added to the acid separately and then upon mixingformed a compatible system.

Examples of some specific surfactants are Brij, Tween (polysorbate),Triton X-100, benzethonium, benzalkonium, dimethyldialkylonium,alkylpyridinium and alkyltrimethylammonium cations with any anion, e.g.,bromide, chloride, acetate or methyl sulfate, non-ionic surfactants suchas silicone-ethylene oxide/propylene oxide copolymers (e.g., OFX-0190,OFX-0193 and OFX-5329 from Dow Corning, Midland, Mich.), Sodium dodecylsulfate (SDS), sodium capryl sulfonate, sodium lauryl sulfate, sodiumlaureth sulfate, cetyltrimethylammonium chloride orcetyltrimethylammonium bromide, methyl tricapryl ammonium chloride, (allavailable from Sigma-Aldrich Co, Milwaukee, Wis.).

It is preferred that the organic cation salts (cationic surfactants) forsurface functionalization are selected not only as ammonium salts aslisted above but may be preferably selected from at least one ofammonium, phosphonium, imidazolium, pyridinium, pyrrolidinium,pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, andtriazolium. For example, phosphonium salts are particularly stable atelevated temperatures and are useful for high temperature applications.Many of the materials belonging to this class of materials are alsocalled ionic liquids, i.e., these are salts with a low melting point sothat at room temperature or at least about below 100° C. these salts arein a liquid form. In addition, the anions of these salts shouldpreferably be halides selected from at least one of chloride, bromideand iodide, and the most preferable being chloride and iodide. Thepreferred salts should also be soluble in the aqueous and the desiredacidic medium.

Embodiment 2

In another embodiment, the corrosion inhibition formulation comprisessurface functionalized particles of low solubility solid materials ascorrosion inhibitor intensifiers (CII). A preferred CII comprisessurface functionalized particles of cuprous salts, especially CuI. Thismeans that the formulation comprises of other corrosion inhibitors, butCII are added to enhance synergistically the corrosion inhibition.Typically CII are used when it is desired that the acids will contactmetals at a temperature greater than about 200° F. Although these CIIsmay be used with any inhibitors, some standard examples of corrosioninhibitors used in the industry are acetylenic alcohols, alkenylphenones, aromatic aldehydes, nitrogen containing heterocyclics,quaternary salts and condensation products of carbonyls and amines,potassium iodide, sodium iodide, lithium iodide. Some the preferredcorrosion inhibitors for use with cuprous salts, particularly CuI belongto the following classes of corrosion inhibiting materials (a) a polymerwhich binds to iodine (b) monomers, (c) phenylpropanoids andcarotenoids, (d) quinolines and (e) an ionic material selected from atleast one of an organic acid, salt of an organic acid and a cationicsurfactant. Additional CII may also be used in the formulation, and someof the preferred CII are water soluble metal salts, including iodidesand sources of water soluble iodides (e.g., NaI, KI). Some of theseclasses of corrosion inhibitors are discussed in more detail below. Alsomany of the corrosion inhibitors discussed in this embodiment may alsobe used along with the other embodiments in this invention.

It is believed that when iodide/iodine are present with corrosioninhibitors, these attach to the metallic surfaces which results incorrosion inhibition, thus polymers that bind strongly to iodine arepreferred so that the metallic surfaces have a superior coverage of acidresisting materials. Since PVP and its copolymers bind strongly withiodine, they represent preferred class of materials for use as corrosioninhibitors which bind strongly with iodine. PVP and its copolymers areused in many applications which relate to food, drugs and cosmetics inlarge quantities with a good safety record. The present invention foundthat PVP and its copolymers along with a source of iodine and when addedto other corrosion inhibitors provided a very high level of corrosionprotection. Thus substituting a part of the corrosion inhibitionformulation partially with the above resulted with low toxicitycorrosion inhibitors. There are other polymers which also bind stronglywith iodine e.g., see Moulay (Molecular iodine polymer complexes, JPolym Eng 2013; 33(5): 389-443). These polymers are used when there is asource of iodine/iodide present in the corrosion inhibition formulation,such as water soluble iodide salts, iodine or even low water solubilitymetal iodide particles which are surface functionalized.

Monomers include vinyl and acetylenic type of materials and shouldpreferably be water soluble or an aqueous solvent which may be formed bymixing water with other solvents, e.g., alcohols. Vinyl monomers and thepreferred acetylenic monomers are depicted by the following generalformulas, where these materials have a acetylinic or a vinyl grouprespectively:

wherein R₆ is preferably selected from hydroxyl, hydroxyalkyl groups sothat these monomers are compatible with aqueous solutions. For Vinylmonomers, R₁, R₂, R₃ and R₄ are preferably selected from hydroxyl,hydroxyalkyl, —H, alkyl, phenyl, substituted phenyl groups, acrylic,acetate, carboxylic and sulfonic groups. Another representation ofacetylenic monomers is as given below:

wherein one of R7, R8 or R9 are preferably a hydroxyl or a hydroxyalkylgroups and the others are the same or are —H, alkyl, phenyl orsubstituted phenyl groups. For example commercially some of thesemonomers are available as propargyl alcohol and from BASF (Germany)under the trade name of Korantin® PP and Korantin® PM.

The corrosion inhibitor may also be selected from one or more ofphenylpropanoids and carotenoids. Phenylpropanoids are derivatives of anamino acid phenylalanine, and a preferred Phenylpropanoid iscinammonaldehyde (e.g., trans-cinammonaldehyde is highly preferred).Quinoline (which includes their derivatives) may also be used in thecorrosion inhibition package. Some of the common quinolines used forcorrosion inhibition of mild steels are quinaldine and quinaldic acid.

The corrosion inhibiting formulation may also comprise ionic materialssuch as organic acids, salts of organic acids, cationic and anionicsurfactants. The general class of organic acids is described in moredetail below. Preferred anionic surfactants have an amine, ammonium,amide and urethane functionality. Some preferred examples of suchanionic surfactants are sodium lauroyl sarcosinate, ammonium laurylsulfate.

Organic acids and salts of the organic acids: These materials may beadded to the mineral acid formulations as co-corrosion inhibitionintensifiers, for example formic acid is also considered a CII,specially under conditions of high temperature (typically about 250° F.)and pressure of about 1,000 psi or higher. Thus the formulation may havemore than one CII including the surface functionalized particles of thisinvention.

Embodiment 3

In another embodiment, the corrosion inhibitor formulation combines atleast three materials of which at least one is a cationic surfactant,the second is a phenylpropoanoid and the third is selected from at leastone of a monomeric material and a nitrogen containing compound. It hasbeen observed that not only does one obtain synergistic effects bycombining these, but also some corrosion inhibitors are superior inlimiting the weight loss while some others at limiting pittingcorrosion, thus providing superior performance as a mixture. It is alsopreferred that the formulation contain a higher weight percentage of themonomeric or the nitrogen containing material as compared to the othertwo constituents. It is also preferred that the monomeric materialand/or the nitrogen containing material and the phenylropanoid togetherexceed the amount of the cationic surfactant by a factor of two or moreby weight and preferably by a factor of 8 or more and most preferably bya factor of 15 or more. A desirable descending concentration order byweight is monomeric component and/or nitrogen containing material,followed by phenylpropanoid and the cationic surfactant. Cations forcationic inhibitors are usually selected from one of ammonium,phosphonium, imidazolium, pyridinium, pyrrolidinium, pyridazinium,pyrimidinium, pyrazinium, imidazolium, pyrazolium, and triazolium. Forexample, phosphonium salts are particularly stable at elevatedtemperatures and are useful for high temperature applications. Thepreferred anions for the cationic surfactants are halides; and of thehalides, chloride and iodide are preferred. Further, the anions have atleast one alkyl chain, with average average lengths in the range of C8(alkyl chain with 8 carbon atoms) or longer, and particularlysurfactants with average C12 to C15 alkyls are most preferred. Preferredmonomeric materials belong to the class of acetylenic monomers,preferably propargyl alcohol and its derivatives and particularly thosewhich contain hydroxyalkyl groups. A preferred phenylpropanoid iscinnamonaldehyde, such as transcinnamonaldehyde. Preferred nitrogencontaining compounds belong to quinolines, PVP and nicotinic acidcontaining materials. The above inhibitor formulation may haveadditional inhibitors and several of them are taught elsewhere in thisspecification. The corrosion effects of the above formulation may beintensified by using any known intensifiers which are compatible withthis formulation including formic acid for high temperature and pressureapplication and those the principles of which are taught in Embodiments2 and 4. For example, any of the first CII (Embodiment 2), second CII(Embodiment 4) and an iodine (iodide) containing compound may be used toimprove or intensify the corrosion inhibition of the formulations ofthis embodiment. Some of the preferred materials from this list are CuI,NaI, KI and chlorides of copper and manganese.

Embodiment 4

In yet another embodiment the corrosion inhibitor formulation comprisesat least two CIIs. The first of these CIIs comprise particles of acuprous salt, and the second CII comprises a metal compound (includingmetal salts) where at least one metal is selected from Li, Na, K, V, Co,Mo, Ta, Sn, Bi, Mn, W and a Cu compound which is different from thefirst CII. All of these metals other than the alkali metals are capableof exhibiting more than one state of oxidation. The metal compounds mayhave high solubility or low solubility in water. If these compounds areinsoluble (or have low solubility, i.e. less than about 100 mg/liter ofwater at room temperature) these can be added as surface functionalizedparticles as described Embodiments 1 or 2. Halide salts of these metalsare preferred; and of the halides, the preferred are chloride andiodide. As another example one may combine CuI particles from Embodiment2 with CuCl₂ to provide a lower cost but high performance intensifier,i.e., partially replacing the more expensive CuI with lower cost CuCl₂.Further, since some CII are superior in limiting weight loss whileothers limit pitting corrosion, a combination provides superiorperformance; or the concentration of a more expensive CII can be loweredto reduce cost but still providing an equivalent or better performance.Since these are CII, this implies that the formulation has at least oneother corrosion inhibitor in addition to the two CIIs. Several of thecorrosion inhibitors have been described in other embodiments.

Embodiment 5

This embodiment relates to formulations used for reduction of ferricions by use of cuprous compounds. These formulations may be made onlyfor ferric ion control, or both for ferric ion control and reduction ofcorrosion (as corrosion inhibitor) due to acid/metal reaction. In casethe cuprous compounds cannot be solubilized in the formulation added tothe acids or are not soluble in acids, these may be used as surfacefunctionalized particles. Use of cuprous compounds results in highlyeffective ferric control formulations. Preferred cuprous compounds arecuprous halides, cuprous oxide and cuprous acetate. Of these a morepreferred compound is CuI.

In this embodiment, CuI is used as a source of both copper and iodine tomake formulations to reduce ferric ions. The reduction of ferric ionsleads to mitigation of ferric ion corrosion and/or reduction of sludgecaused by interaction of ferric ions and the crude oil. This embodimentalso envisages the use of CuI both as a generic corrosion inhibitor(Embodiment 1) or corrosion inhibitor intensifier (CII) (Embodiment 2)along with the ability to reduce ferric ion concentration. For ferricion reduction one may further incorporate additional reducing agents,and optionally additional iodide ions may also be added. Preferredadditional iodide sources (or iodine containing compounds) are alkalimetal iodides, alkali-earth metal iodides, iodine-polymer complexes.Since addition of sulfur compounds in formulations may potentiallyconvert to a food source for anaerobic bacteria (sulfate reducingbacteria) in the wells which are also responsible for MIC and productionof poisonous H₂S gas, it is preferred not to use sulfur compounds asreducing additives. HExamples of some of the preferred reducing agentsare organic acids and their salts, such as ascorbic acid, sodiumascorbate, erythorbic acid, sodium erythorbate citric acid and citrates.These ferric control formulations are usually added to acids along withinhibitors so that both inhibition and ferric control is achieved whenthese acids (or inhibited acids) are used to treat wells. Cuprouscompound containing inhibitors may naturally provide iron control,particularly those which also have a reducing agent. It is to be notedthat in some cases surface functionalizing agents (e.g., in Embodiment2) may be the same as reducing agents or may have reducing properties,such as ascorbic acid. In some cases the inhibitors may also providereducing properties, as ascorbic acid has also been used as an acidinhibitor.

In another variation of the current embodiment, any ferric ion reducingcomposition may be added to the corrosion inhibitors of Embodiment 3 toresult in those compositions which result both in effective ferric ionreduction and also in superior corrosion protection of metallicmaterials against acidic corrosion. These ferric ion reductioncombinations may contain reducing agents along with other ingredientssuch as sources of copper and iodide ions.

EXAMPLES Example 1: Evaluation of Corrosion Protection of Various Steels

Various steels were evaluated for corrosion protection using a solutionof 15% HCl. This acid had been on the shelf for many years, thus theseresults are comparable to each other, but not using fresh acid which wasperformed on several samples as discussed in other examples below. Thetemperature of exposure was 60° C. The time of exposure was 20 hours. Ineach case 10 ml of acid was used, unless mentioned otherwise in theother examples below, the acid volume in all evaluations was 10 ml.Different steels had different shapes and masses, and the mass variedfrom 0.6 to 3 g but were comparable for a given steel type. Two sampleswere placed in each 10 ml volume of acid. An inventive formulation F1was made by grinding CuI powder in a wet grinding mill produced byNetzsch Premier Technologies LLC (Exton Pa.), equipment model wasMinicer®. Copper iodide, sodium iodide, polyvinvylpyrrolidone K17, anddeionized water were combined as described in the Table 5. Thesematerials were processed together in the mill using 100 micron grindingmedia (3M™ Micro Milling Media ZGC) at a mill speed of 4200 RPM andrecirculation pump speed of 600 RPM. The formulation used for F1 wassample 7.

TABLE 5 Grinding Sample # CuI (g) PVP (g) NaI (g) DI-Water (mL) Time(min) 1 9 40 1 150 1000 2 9 2 1 200 350 3 9 2 0.25 200 1200 4 9 0.9 0.1200 450 5 9 0.95 0.05 200 350 6 18 1.95 0.05 200 1000 7 90 9 1 140 350 890 9.5 0.5 200 1330

Each milled product appeared as a semi translucent opalescent dispersionthat was stable against settling with particle sizes around 10-30 nm.The dispersions were dried to form purple colored solids under reducedpressure. Subsequent redispersal formed dispersions similar to thosebefore drying with particle sizes around 10-30 nm. The results in Table6 show that the inventive materials when present in 15% HCl weresuperior on all steels as compared to 15% HCl solution (without anyadditive) due to lower weight loss.

TABLE 6 Evaluation in 15% HCl, 20 hrs at 60° C. Metal (steel type)Additive Mass Loss ST Dev (n = 2) 1018 None 21.26% 0.53% 1018 60 ppm Cuas F1 7.06% 0.31% A516 None 4.98% 0.27% A516 60 ppm Cu as F1 0.34% 0.01%4130 None 24.66% 8.02% 4130 60 ppm Cu as F1 0.78% 0.02% 304* None 25.91%1.18% 304* 60 ppm Cu as F1 0.60% 0.09% *high chrome stainless steel

Example 2: Evaluation of Corrosion Protection Using Different Sources ofCopper Ions

In this experiment, the inventive formulation F1 was evaluated againstother sources of copper at 60 ppm in the acid.

This experiment used cut shapes from a steel piece in a thickness of0.025 inch (0.64 mm). The results show that the inventive formulation F1was most effective due to the least weight loss. The acid source wassame as in the earlier example. Three samples were placed in each volumeof 10 ml acid.

TABLE 7 1 Week @ 60° C., 4130 steel, 15% HCl % Mass Sample AdditiveLoss* St. Dev (n = 3) RSD, % A None 38.3% 3.1% 8% B 60 ppm Cu as F1 3.9%0.3% 9% C 60 ppm Cu as Bulk CuI 39.8% 7.5% 19% D 60 ppm Cu as Cu(II)Cl₂47.2% 19.4% 41% *Initial sample weight in g varied between 0.58 to 0.75g

Example 3: Comparison of Corrosion Inhibition by CuI Formulation vs.Glutaraldehyde

In this experiment, punched circular discs of 1 cm in diameter wereused. Freshly procured acid from Sigma Aldrich was used in thisexperiment and also on all of the subsequent experiments unlessmentioned otherwise. In all cases where 1 cm diameter discs were used,two discs were placed in each 10 ml volume of the acid unless mentionedotherwise. Thickness of the sheet was 0.025 inch (0.64 mm) and theweight was about 0.4 g. Unless mentioned otherwise in all examples thethickness of 4130 steel was the same. 4130 is a medium carbon steel withsmall content of Cr and Mo. Inventive formulation F1 was compared withglutaraldehyde—a very popular biocide used in the oil and gas industry.These results (Table 8) demonstrate the superiority of inventivematerial in inhibiting corrosion. As seen in the table from this testglutaraldehyde had no effect in inhibiting corrosion. Thuscomparatively, the inventive material F1 is highly effective, both asbiocide (see published US patent application 2014/0271757) and as anacid corrosion inhibitor. Corrosion inhibition is shown below in Table8.

TABLE 8 1 Week @ 60° C., 4130 steel, 15% HCl Sample Additive % Mass LossSt. Dev (n = 2) A None 100.00% 0.00% B 60 ppm Cu as F1 13.41% 4.58% D 60ppm glutaraldehyde 100.00% 0.00% E 20 ppm Cu as F1 17.39% 1.44% G 20 ppmglutaraldehyde 100.00% 0.00%

Example 4: Evaluation of Various Additives on Inhibition Properties ofCuI

As mentioned in Example 3, this and the subsequent corrosion examples(experiments) were conducted using fresh acid. One cm diameter steelshapes were punched from the sheet as before. In this example, the CuIsource in all cases was bulk copper iodide. Although bulk CuI and itscombination with other materials was better than using no additive, theresults show that the combination of CuI and PVP gave the best results,and the results were remarkably superior as compared to the othermaterials.

TABLE 9 Impact on 4130 steel after 1 Week of exposure at 60° C. in 15%HCl % Mass STDev Sample Additive Loss (n = 2) A None 100.00% 0.00% B CuI(60 ppm) 73.85% 20.97% C CuI (60 ppm) + PVP (18 ppm) 13.64% 2.39% D CuI(60 ppm) + PEG (18 ppm) 63.81% 1.00% E CuI (60 ppm) + Polyacrylamide (18ppm) 54.83% 0.33% F CuI (60 ppm) + Benzotriazole (18 ppm) 88.96% 11.05%G CuI (60 ppm) + SLS (18 ppm) 81.79% 15.53%

Example 5: Corrosion in Brine

In this example, brine was prepared (to simulate produced water from oilwells) by dissolving 5% NaCl by weight in DI water. 10 ml of brine wasused for each experiment. The samples were cut from sheets of thesesteels and varied slightly in weight and shape. Inventive formulation F1was used as a source of copper which was present at 60 ppm (as Cu).After 20 hrs at 60° C., the brines containing copper additive showeddeposit of copper on the steels. In a subsequent experiment no suchdeposition was seen on aluminum or a plastic substrate.

Additional samples were made where half (50%) of the steel surface wascovered by a polymeric tape. When these were treated with brine (10 ml)containing 60 ppm Cu as earlier, the non-covered portions showeddeposition of copper. The tape was removed and the plates with about 50%surface covered with copper (and as control steel sheet without copper)were put in fresh brine (no copper in the solution) at 60 C for 38 daysfollowed by 14 days at 85° C. No additional corrosion was observed onsteel sheets covered by copper in 50% of the area as compared tonon-covered sheets. This shows that there was no galvanic action betweencopper and steel. This showed that use of surface functionalized CuIparticles with PVP as the source of copper did not lead to enhancedcorrosion.

Example 6: Effect of PVP and its Copolymers on Corrosion Inhibition

PVP and its copolymers are particularly important because of theirstrong binding with iodine and low toxicity. 1 cm diameter discs weresubjected to 15% HCl (10 ml) for 20 hours. The samples were evaluatedand put back in the corrosion medium for a total of 1 week and thenre-evaluated. K17 and VA64 are respectively PVP polymer (with weightaverage molecular weight of about 7,000 to 11,000) and PVP-Poly vinylacetate copolymer (with weight average molecular weight of 45,000 to70,000, with 40% being vinyl acetate), both from BASF. Ganex 904 and 516are polyolefin PVP copolymers from Ashland (New Milford, Conn.). Ganex904 is a butylated polyvinylpyrrolidone (PVP) consisting of 10% olefin.Ganex 516 is similar to Ganex 904 and consists of 50% hexadecyl alkyland 50% polyvinylpyrrolidone and is not soluble in water. Styleze CC-10and Conditioneze NT-20 are also copolymers from Ashland. Styleze CC-10is a copolymer of vinylpyrrolidone (monomer of PVP, same as PVPcopolymer) and dimethylaminopropyl methacrylamide and is soluble inwater. Conditioneze NT-20 is a copolymer of vinylpyrrolidone andmethacrylamidopropyl trimethylammonium chloride. 1ethyl2pyrrolidone wasa non-polymeric nitrogen containing material, the type of materialcombined with CuI in prior art for corrosion enhancement. Results areshown both after 20 hours and 1 week at 60 C in 15% HCl. In all casesother than F1, the source of CuI used was bulk CuI material.

The results after 20 hours (Table 10) show that CuI by itself and thenon-polymeric nitrogen containing material along with 60 ppm copper wereeffective, however all other materials containing both CuI and the PVPand its PVP copolymers were much more effective. This shows that all ofthe PVP's and their copolymers were effective in inhibiting corrosionwhen used with CuI. Further as seen in samples 13 to 15, corrosioninhibition is also a function of the concentration of the inhibitor. Itis surprising that surface functionalized particles of CuI by PVP wereshowing reduced corrosion when it was present in a very lowconcentration as seen in sample 14.

TABLE 10 Comparison of various PVP polymers (including copolymers) in15% HCl on 4130 steel for 20 hrs exposure at 60 C. Sample Additive Cu %Mass Loss STDev (n = 2) 1 NONE  0 ppm 55.54% 0.05% 2 CuI Alone 60 ppm15.28% 0.12% 3 PVP-K17 60 ppm 1.20% 0.21% 4 PVP-MW10K 60 ppm 1.33% 0.11%5 PVP-MW55K 60 ppm 1.66% 0.15% 6 PVP-MW1.3MIL 60 ppm 2.09% 0.26% 7 VA6460 ppm 1.76% 0.06% 8 GANEX904 60 ppm 1.89% 0.44% 9 GANEX516 60 ppm 3.93%1.72% 10 STYLEZE CC-10 60 ppm 2.77% 0.70% 11 CONDITIONEZE 60 ppm 2.32%0.12% NT-20 12 1ethyl2pyrrolidone 60 ppm 10.24% 0.77% 13 F1 60 ppm 1.51%0.02% 14 F1 10 ppm 9.19% 0.32% 15 F1  1 ppm 55.30% 0.36%

The one week results separated the performance of the materials furtheras shown in Table 11. This brings out the distinction more clearlybetween various molecular weights of PVP. The 1.3 million mol wt PVP waseffective; however, the lower molecular weight materials were moreeffective. This also shows that the various PVP copolymers were alsoeffective corrosion inhibitors as seen from the mass loss and also lowerstandard deviation.

TABLE 11 Comparison of various PVP polymers (including copolymers) in15% HCl on 4130 steel after one week exposure at 60 C. STDev SampleAdditive Cu % Mass Loss (n = 2) 1 NONE  0 ppm 100.00% 0.00% 2 CuI Alone60 ppm 69.91% 42.55% 3 PVP-K17 60 ppm 13.17% 1.30% 4 PVP-MW10K 60 ppm10.00% 0.43% 5 PVP-MW55K 60 ppm 8.04% 1.02% 6 PVP-MW1.3MIL 60 ppm 30.76%3.90% 7 VA64 60 ppm 13.33% 1.49% 8 GANEX904 60 ppm 17.85% 4.58% 9GANEX516 60 ppm 86.34% 4.33% 10 STYLEZE CC-10 60 ppm 31.69% 6.58% 11CONDITIONEZE NT-20 60 ppm 53.47% 1.90% 12 (1ETHYL2PYRROLIDONE) 60 ppm69.96% 39.67% 13 F1 60 ppm 15.36% 0.04% 14 F1 10 ppm 100.00% 0.00% 15 F1 1 ppm 100.00% 0.00%

Example 7: Evaluation of Additional Polymers and Glutaraldehyde with Cu

This table compares addition of Cu as bulk CuI (other than for thesample containing F1 which has CuI present as functionalized particles)into acidic solutions of various polymers and also to acidic solution ofgluteraldehyde. The various polymers include PVP, polyacrylamide(Aldrich 434949, 10,000 MW), polyacrylic acid (Aldrich 416029, 8000 MW),polyvinylalcohol (Aldrich 36027, 9,000-10,000 MW), and polyethylenimine(Aldrich 468535). The 20 hour results show that CuI (bulk) with K17 PVP(sample 3) and F1 (sample 8, which is CuI particles surfacefunctionalized by K17 PVP) are better performing, but all of the otherpolymers also reduced corrosion. Although F1 and CuI (Bulk)+K17 PVP haveclose inhibition characteristics, but F1 is much easier to disperseuniformly in the acid.

TABLE 12 Impact of CuI addition to various polymers and glutaraldehydein 15% HCl on 4130 steel, after 20 hrs at 60 C. Sample Additive Cu %Mass Loss STDev (n = 2) 1 None  0 ppm 49.75% 5.16% 2 None 60 ppm 17.30%15.52% 3 PVP-K17 60 ppm 2.86% 0.80% 4 Polyacrylamide 60 ppm 2.96% 0.60%5 Polyacrylic acid 60 ppm 2.80% 0.60% 6 Polyvinylalcohol 60 ppm 11.30%11.60% 7 Polyethylene imine 60 ppm 8.68% 0.49% 8 F1 60 ppm 1.59% 0.09%

After 1 week under these conditions (Table 13), it is apparent that F1and Bulk CuI with K17 were vastly superior. These results consistentlydemonstrate superior corrosion efficacy when CuI is added to PVPcontaining polymers.

TABLE 13 Impact of CuI addition to various polymers and glutaraldehydein 15% HCl on 4130 steel after 1 week exposure at 60 C. Sample AdditiveCu % Mass Loss STDev (n = 2) 1 None  0 ppm 98.62% 1.95% 2 None 60 ppm75.58% 28.35% 3 K17 60 ppm 13.43% 2.21% 4 Polyacrylamide 60 ppm 63.62%14.95% 5 Polyacrylic acid 60 ppm 49.83% 2.61% 6 polyvinylalcohol 60 ppm66.45% 13.98% 7 polyethtleneimine 60 ppm 71.31% 31.31% 8 F1 60 ppm11.52% 0.35%

Example 8: Comparison of CuI, PVP, KI and their Influence on Each Other

Water soluble alkali iodides (source of iodine) are used to furtherenhance the corrosion inhibition. In these experiments, the iodine(iodide) content was kept the same in samples B through E. The resultsshow that presence of copper iodide is important. Addition of only KI insample D did not inhibit corrosion, but had a larger impact when mixedwith PVP (K17). The best performing material was CuI+PVP as seen forweight loss of sample C in Table 14, but also combining PVP to a sourceof iodine (CuI or KI) reduced corrosion.

TABLE 14 Impact of PVP and KI as compared to CuI (4130 steel, 15% HCl,60 C., 20 hrs) Sample Additive 1 % Mass Loss STDev (n = 2) A None 63.55%1.08% B CuI (60 ppm Cu)* 25.07% 2.17% C CuI + PVP (60 ppm Cu+ 2.26%0.48% 18 ppm PVP)* D KI (120 ppm I from KI) 71.79% 0.74% E KI + PVP (120ppm I from KI+ 12.36% 1.39% 18 ppm PVP) *These samples have 120 ppmiodide from CuI.

Example 9: Corrosion Inhibition Potential of Various Copper Salts

In this experiment various copper salts (at 60 ppm copper concentration)were evaluated by themselves against A516, a carbon steel. The steelabout ⅙^(th) inch (1.6 mm) thick was cut in a size of about 1 cm by 1 cmand evaluated in 10 ml of 15% HCl. These results in Table 15 show thatof all the copper salts tested only CuI showed significant corrosioninhibition. One should note that some of the copper salts used such asCu(II)Cl are highly water soluble. Further, as a comparison, thecorrosion inhibition was much more significant with this steel when CuIwas used as surface functionalized particles (with PVP) (see alsoresults on steel A516 in Table 6).

TABLE 15 Impact of various copper salts (cuprous and cupric) at 60 ppmcopper concentration on corrosion in 15% HC1 at 60° C. for 20 hours.Sample Additive % Mass Loss 1 None 17.11% 2 Cu(I)I  7.51% 3 Cu(I)Br14.74% 4 Cu(I)Cl 13.85% 5 Cu(I)O 14.18% 6 Cu(I)Acetate 17.17% 7Cu(I)Thiocyanate 15.31% 8 Cu Metal 14.90% 9 Cu(II)Cl₂ 13.48% 10 Fl 0.49%

Example 10

Various natural polymers or ingredients were evaluated with 60 ppmcopper (as bulk CuI) for seeing if they offer corrosion protection of4130 steel against 15% HCl. The results were compared with PVP. Thesewere evaluated for 20 hrs at 60° C. The results (Table 16) show that allof these polymers and materials worked better as compared to a case withno additive, but PVP was superior as compared to the others and Chitosanalso looked promising. When one compares these results from those inTable 14, it appears that for materials other than PVP and Chitosan, thecontribution of the other materials towards corrosion was marginal,since a significant contribution is perhaps made by the addition of CuI.

TABLE 16 Evaluation of various materials in 15% HCl for 20 hrs at 60 C.on 4130 steel Sample Polymeric Additive* % Mass Loss STDev (n = 2) 1None 59.88% 1.93% 2 Agarose 14.76% 0.55% 3 K17 (PVP) 2.17% 0.07% 4Chitosan 7.25% 0.31% 5 Carboxy methyl cellulose 18.15% 5.13% 6 Glycerin20.69% 1.17% 7 Corn Starch 19.02% 1.11% *All of these formulations(excepting sample 1) had 60 ppm added as bulk CuI. Sample B in Example24 shows that when only bulk CuI is present at a copper concentration of60 ppm, mass loss was 25.07%.

Example 11: Corrosion Inhibition of High Chromium Steel

In this experiment the ferrous alloy was a stainless steel 304(composition of such steel is 18%-20% Cr, 8-12% Ni, 2% Mn, 0.75% Si,0.08% C in iron). These steels are known for their high corrosionresistance. Their corrosion resistance to 15% HCl was measured afterexposing them at 60° C. for 20 hours and also at 100° C. for 6 hours.Two punched discs of 1 cm diameter (thickness 0.025 inch or 0.64 mm)were put in 10 ml of acid in each case. Cu concentration was varied andwas added as formulation F1 (surface functionalized CuI particles withPVP where the composition for 60 ppm copper as CuI, 18 ppm PVP and 1.8ppm NaI). The other components increase in the same proportion withincreasing copper concentration. The results are also compared to bulkCuI in a concentration of 60 ppm Cu.

Data at both temperatures show that with increasing copper concentrationcorrosion is reduced. Increasing the temperature from 60 to 100 Cincreases the corrosion rate significantly, and thus requires higheramount of additive for protection. Addition of bulk CuI does not protectthe steel to the same degree as the inventive formulation F1. It isimportant to know the well conditions accurately so that the additivepackage (and its concentration) can be designed accordingly.

TABLE 17 Evaluation and comparison of Inventive formulation at variousconcentrations % Mass Loss Sample Cu conc ppm at 60° C., 20 hrs % MassLoss at 100° C., 6 hrs A 0 71.22% 53.12% B 60 as F1 1.97% 22.73% C 300as F1 8.58% D 600 as F1 0.26% 2.10% F 60 as Bulk 32.30%

Example 12: Corrosion Inhibition of Functionalized CuI Particles withFurther Additions of PVP and NaI at 85° C.

In this example corrosion of stainless steel (SS) 304 discs as in theearlier example was evaluated against 15% HCl at 85° C. for six days ofexposure. This was a very aggressive test which was at highertemperature and also a longer period. The purpose of this test was tostart with those corrosion inhibitor compositions which worked inearlier tests and improve the compositions further for these elevatedtemperatures and long times. In addition to adding copper as formulationF1 (CuI/PVP/NaI), more PVP and NaI was added as shown in Table 18 so asto evaluate different concentrations of the additives. These resultsshow that the amounts of all of the three components, i.e., non-alkalinesalt (CuI in this case) water soluble alakali halide (NaI) and bindingagent PVP play an important role. Comparing the best performing sample8, with samples 4 and 9 shows that eliminating or reducing CuI by halfhas severe consequences. Comparison of the results on sample 8 withthose on sample 7 shows that reducing NaI by half also has a severeimpact on the results. Comparing sample 8 with sample 6 demonstratesthat the amount of PVP is also important. Thus in a corrosion resistantformulation all three are required in careful proportions so that onecan achieve high corrosion resistance at the lowest possible amount ofthe additive.

TABLE 18 Corrosion comparison at 85° C. for six days in 15% HCl on SS304 Cu as F1, Added PVP, Added NaI, % Mass Sample ppm ppm ppm Loss 1 300900 100 100.00% 2 300 900 200 56.01% 3 300 1800 100 100.00% 4 300 1800200 55.59% 5 600 900 100 100.00% 6 600 900 200 14.84% 7 600 1800 10091.52% 8 600 1800 200 3.23% 9 0 1800 200 88.76%

Example 13: Corrosion Inhibition of Functionalized CuI Particles withFurther Additions of PVP and NaI at 100° C.

This experiment was conducted on SS 304 discs. As usual, the acid volumewas 10 ml and two 1 cm diameter disc were put in each vessel. Theresults show that seperate and further addition of PVP or NaI bothincrease the efficacy of the formulation F1 containing CuI, PVP and NaI.

TABLE 19 Comparison at 100° C. for 6 hrs, for samples containing CuI,PVP and NaI in different proportions Cu, PVP, NaI, % Mass STDev Sampleppm ppm ppm Loss (n = 2) A 300 as Bulk 13.38% 0.97% B 300 as F1 6005.31% 0.76% C 300 as F1 100 3.40% 1.69% D 300 as F1 200 2.18% 0.43% E600 as F1 1800 200 1.01% 0.65%

The results from this and Example 28 demonstrate the need forinformation on the corrosion conditions in order to design a effectiveinhibitor composition.

Example 14: Use of Alternative Binding Agents and Comparison to PVP at85° C.

In this example corrosion of stainless steel (SS) 304 discs as in theearlier example was evaluated against 15% HCl. The test was conducted byexposing the discs to the acid at 85° C. for 20 hours. In each case thesource of CuI was inventive formulation F1 (see Example 1), in somecases F2, F3 and F4 were also used which were made using FI and addingmore ingredients as described below in the proportions described below:

-   -   F2=600 ppm Cu as F1 (which includes CuI, PVP and Na)+200 ppm NaI    -   F3=600 ppm Cu as F1 (which includes CuI, PVP and Na)+1800        PVP+200 NaI    -   F4=300 ppm Cu as F1 (which includes CuI, PVP and Na)+1800        PVP+200 NaI

In each flask containing 10 ml acid, two discs were used (1 cm diameter,0.64 cm thick) and the appropriate inhibitors added. In this experimentwe also evaluated ndodecylpyridinium chloride (DDPC),benzyldimethylhexadecylammonium chloride (BAC) and proargyl alcohol asbinding agents, all of these have been used by themselves as corrosionprotection agents (corrosion inhibitors). The first two materials areorganic cationic salts and the last one a polymerizable monomer. Theresults show that under these conditions when 600 ppm Cu is added as F2(which contains CuI+PVP and NaI) to either DDPC, BAC, or propargylalcohol (PA), corrosion is highly reduced, which shows that materials ofthis invention may be added to the conventional corrosion agents ascorrosion inhibition intensifiers. Further when DDPC, BAC, and proargylalcohol (samples 1, 3 and 6) are used with potassium iodide (KI) atypical iodide additive which also is used for corrosion inhibitionintensification. The results show that dispersible CuI also leads tocorrosion inhibition intensification.

TABLE 20 Comparisons at 85° C. for 20 hrs in 15% HCl Corrosionprotection Ppm (Additive), % Mass STDev Sample agent at l,800 ppm sourceof additive Loss (n = 2) 1 DDPC None None 92.61% 0.73% 2 DDPC 60 ppm CuF1 7.95% 1.23% DDPC 600 ppm Cu F2 0.43% 0.42% 3 DDPC 200 (No Cu) KI13.35% 0.70% 4 BAC None None 100.00% 0.00% 5 BAC 60 ppm Cu F1 30.50%2.14% BAC 600 ppm Cu F2 0.43% 0.06% 6 BAC 200 (No Cu) KI 21.35% 2.65% 7Propargyl Alcohol None None 100.00% 0.00% 8 Propargyl Alcohol 60 ppm CuF1 25.45% 1.48% Propargyl Alcohol 600 ppm Cu F2 1.61% 0.65% 9 PropargylAlcohol 200 (No Cu) KI 16.05% 3.38% 10 F3 (300 ppm Cu) None None 4.47%1.61% 11 blank control None None 100.00% 0.00%

Example 15: Evaluation of Dispersible CuI, KI and PVP when Added to DDPC(Cationic Salt) Corrosion Inhibitor in 15% HCl at 85° C.

Sample 1 in Table 21 shows that DDPC by itself in the concentration usedwas not effective. When KI, PVP or CuI were added, the corrosioninhibition intensification was sharp. Samples 13, 14 and 15 did not usedispersible CuI, with heat and temperature eventually CuI particlesseemed to have dissolved. For example, when 300 ppm Cu as bulk CuI isadded to 15% HCl, it quickly settles to the bottom (see FIG. 1), whereaswhen the formulation in sample 12 is used the result is a translucentsolution of well suspended particles throughout the solution. The latterproperty is very convenient in the field where components are mixed andone of them disperses uniformly right away, vs another material whichmay require stirring/heating, etc. for extended period of time.

Results on sample 4 and sample 15 show that the use of dispersible CuIand bulk CuI produce about equivalent inhibition. It should be noted CuIin sample 4 is dispersible and not in sample 15, however at theseconcentrations and the temperature of testing bulk CuI dissolves in theacidic media. However, it is not practical in the field to usenondispersible materials as one needs the inhibitor to be in acompletely dispersed form in a liquid medium so that it can be meteredby pumping into the acid. Samples 7, 8 and 9 show that combining CuIwith PVP and then with NaI decreases corrosion in each step. Similarlycomparing samples 2 and 4, it is seen that addition of CuI (as F1) ismore effective as compared to the addition of KI in reducing corrosion.

TABLE 21 Comparisons SS 304 discs at 85 C. for 20 hrs in 15% HCl ppm Cu,ppm, ppm, ppm, % Mass STDev Sample source Additive 2 Addtive 3 Additive4 Loss (n = 2) 1 1800 DDPC 75.84% 0.37% 2 1800 DDPC 200 KI  11.27% 1.78%3 60 F1 1800 DDPC 200 KI  3.47% 0.13% 4 60 F1 1800 DDPC 6.02% 2.88% 5 60F1 1800 DDPC 360 PVP 7.07% 2.72% 6 60 F1 1800 DDPC 360 PVP 40 NaI 4.04%0.62% 7 60 F1 86.12% 7.55% 8 60 F1 360 PVP 24.19% 0.54% 9 60 F1 360 PVP40 NaI 18.54% 0.66% 10 60 F1 1800 DDPC 360 PVP 40 NaI 4.04% 1.07% 11 120F1  1800 DDPC 720 PVP 80 NaI 2.05% 0.07% 12 300 F1  1800 DDPC 1800 PVP 200 NaI  0.97% 0.19% 13  300 Bulk 1800 DDPC 0.93% 0.24% 14  120 Bulk1800 DDPC 2.55% 0.58% 15   60 Bulk 1800 DDPC 5.67% 0.09%

Example 16: Evaluation of DDPC and Proagryl Alcohol Based Formulationsat 100° C.

Propargyl alcohol is a polymerizing additive which is known to beeffective at higher temperatures, particularly in the presence of KI.This experiment was carried out to investigate the corrosion resistanceof this material as compared to an inventive formulation. The experimentwas conducted using Sample 1 is an inventive formulation vs the othertwo samples which had potassium iodide. This shows that that theinventive formulation which used F1 and NaI as corrosion intensifierswith DDPC inhibitor was more effective as a corrosion inhibitor package.

TABLE 22 Comparison of corrosion inhibition at 100 C. for 6 hrs in 15%HCL using SS 304 discs Cu Corrosion additive, inhibitor, Salt, % MassSTDev Sample ppm ppm ppm Loss (n = 2) 1 300 as F1 DDPC, 1800 NaI, 2001.31% 0.70% 2 None DDPC, 1800 KI, 200 9.83% 0.42% 3 None Propargyl, 1800KI, 200 41.56% 0.28%

Example 17: Comparative Performance with 600 ppm Cu Formulations at 85°C. Using SS304 Spheres

It was noticed that when the amount of corrosion was less than about 2%,in many cases the results had considerable scatter. This may have beenbecause of the stress put on the discs while punching them out of thesheets, and also poor edges which in some cases could corrode faster andfall off. Thus it was decided to replace the discs with polished balls(spheres) diameter 9/32 inch (7.1 mm) with a mass of about 1.5 g andmade out of SS304. In these experiments only one ball was put in eachvial containing 10 ml acid.

All of the samples in Table 23 had 600 ppm of copper (other than sample1). Sample 8 shows that although CuI as bulk at 600 ppm shows goodcorrosion resistance at 20 hr, but is poor when the samples areevaluated after 1 week. All of the other inventive samples (samples 2,3, 4, 5 and 7) performed well after 1 week. As pointed out earlier,sample 6 was not properly dispersible. Although the two PVP's i.e., K17(average molecular weight Mw was 9,000 and Mn was 2,000) and PVP-MW55k(average molecular weight Mw was 55,000), performed equivalently interms of corrosion inhibition, but when higher concentrations of thesematerials are used (such as for formulations to work at highertemperatures), the viscosity for PVP-MW55K will be higher.

TABLE 23 Comparative inhibitor performance with 600 ppm Cu on steelballs at 85 C., 20 hrs and 1 week in 15% HCl Cu, Source CorrosionSoluble % Loss % Loss (1 Sample ppm of Cu inhibitor, ppm iodide ppm (20Hr) Week) 1 58.33% 75.04% 2 600 F1 PVP 1800 NaI 200 0.10% 2.17% K17 3600 F1 PVP- 1800 NaI 200 0.11% 2.42% MW55K 4 600 F1 PVP- 1800 NaI 4000.04% 1.36% MW55K 5 600 F1 PVP- 1800 NaI 600 0.07% 1.57% MW55K 6 600 Cuas DDPC 1800 0.05% 1.32% Bulk* 7 600 F1 DDPC 1800 NaI 200 0.11% 2.21% 8600 Cu as 0.66% 46.34% Bulk* *Bulk CuI powder as obtained, prior to theformation of functionalized particles . . .

Example 18: Evaluation of Steel Spheres with Formulations withFunctionalized Particles of CuI at 85° C.

Additional experiments were conducted on SS304 steel balls as in theearlier example. The diameter of these was 9/32 inch (7.1 mm) with amass of about 1.5 g. Table 25 shows results at 85 C and for 20 hours ofexposure in 15% HCl. These results show that all of the inventiveformulations worked well (compare results from Table 23, sample 1).These results show that the corrosion resistance increases withincreasing copper iodide content, and with increasing amounts of CuI,one can decrease the concentration of the other additives.

TABLE 24 Evaluation of inhibition of SS304 balls at 85° C. for 20 hrsSample Additive 1 Additive 2 Additive 3 % Loss 1 300 Cu as F1 1800 PVPK17 200 NaI 0.24% 2 120 Cu as F1 1800 PVP K17 200 NaI 0.72% 3 60 Cu asF1 1800 PVP K17 200 NaI 1.41% 4 300 Cu as F1 0.35% 5 120 Cu as F1 3.28%6 60 Cu as F1 13.76%

Example 19: Check on Result Reproducibility and Performance Comparisonof Several Formulations Using SS304 Balls when Exposed at 100° C.

These experiments were also carried out using steel balls as describedin the earlier experiments. The temperature was boiling (nominally 100°C.) and the exposure time was 6 hours in 10 ml of 15% HCl. Samples 6 to10 were repeats to check the consistency of the procedure. The resultsshow good consistency. The results show (sample 3) that addition of 1000ppm Cu (added as 3,000 ppm of CuI) reduces corrosion significantly.However, about the same corrosion is seen in samples 15 and 16 with muchlower copper content. Experiments 15 and 16 bulk CuI or thefunctionalized particles of CuI, formulation F4 (with PVP and NaI).Although the corrosion results were similar, bulk CuI is notdispersible. Addition of CuI to DDPC was more effective as compared tothe addition of KI (compare samples 12, 13 to sample 14). In addition,introducing CuI and KI to DDPC further increased the inhibition (comparesamples 14 and 16).

TABLE 25 Corrosion of SS 304 balls at 100 C. for 6 hours in 15% HCl Sam-ppm Cu, ppm, ppm, ple source of CuI Additive 2 Additive 3 % Loss 154.83% 2 300 Cu as Bulk 4.73% 3 1000 Cu as Bulk 0.25% 4 300 Cu as F11800 Poly- 200 NaI 1.22% acrylamide 5 600 Cu as F3 0.78% 6 300 Cu as F40.64% 7 300 Cu as F4 0.45% 8 300 Cu as F4 0.67% 9 300 Cu as F4 0.70% 10300 Cu as F4 0.40% 11 1800 DDPC 19.34% 12 1800 DDPC 200 KI 6.38% 13 1800DDPC 1800 KI 1.32% 14 300 Cu as CuI Bulk 1800 DDPC 0.85% 15 300 Cu as F41800 DDPC 0.33% 16 300 Cu as CuI Bulk 1800 DDPC 200 KI 0.33%

Example 20: Comparative Efficacy of CuI Nanoparticles with Bulk CuI andNaI

CuI as bulk material, CuI as formulations F1, and NaI were combined withpropargyl alcohol (PA) or dodecylpyridinium chloride (DDPC) in 15% HCland tested for corrosion inhibition as in Example 19. Samples 1-3 & 5-7have equivalent iodide concentrations. The results demonstrate that theaddition of insoluble CuI performs better that soluble NaI at equivalentiodide concentrations (compare examples 1-3 & 5-7). The results alsodemonstrate that dispersible CuI performs equivalent to nondispersiblebulk CuI (compare examples 2-3 & 6-7).

TABLE 26 Corrosion of SS 304 balls at 100 C. for 6 hours in 15% HCl ppmCu, Sample source of CuI ppm NaI ppm PA ppm DDPC % Loss 1 0 709*  2000 00.90% 2 300 Cu as Bulk 0 2000 0 0.29% 3 300 as F1 0 2000 0 0.32% 4 0 02000 0 31.97% 5 0 709  0 2000 2.81% 6 300 Cu as Bulk 0 0 2000 1.08% 7300 as F1 0 0 2000 0.98% 8 0 0 0 2000 20.99% *Corresponds to 600 ppm ofiodide (same as in CuI which has 300 ppm of Cu)

Example 21: CuI with Two Corrosion Inhibitors, Propargyl Alcohol andTrans-Cinnamaldehyde

CuI as F1 was combined with propargyl alcohol and/ortrans-cinnamaldehyde in 15% HCl and tested for corrosion inhibition asin Example 19. The results demonstrate that satisfactory corrosion ratesare attained with low amounts of dispersed copper iodide along with apropargyl alcohol or trans-cinnamaldehyde and with combinations thereof.Samples 8-11 demonstrate a synergistic effect between propargyl alcoholand trans-cinnamaldehyde when combined with dispersed CuI as F1. InSamples 1 to 9, the total amount of corrosion inhibiting formulation wasat 0.3% (or 3,000 ppm). Combination of two corrosion inhibitors withfunctionalized CuI particles combined in the proportion shown in Sample8 resulted in the best performance. Sample 4 and 10 have comparableperformance, but sample 10 has lower amount of additive. In corrosioninhibition, it is often seen that at a certain additive concentrationone reaches the maximum inhibition under specified conditions (e.g.,additive type, temperature, time, acid solution used and the type ofmetal exposed)). Addition of more additive does not result inappreciable change in corrosion inhibition.

TABLE 27 Corrosion of SS 304 balls at 100 C. for 6 hours in 15% HCl ppmppm, ppm propargyl trans- Sample Cu as F1 alcohol cinnamaldehyde % Loss1 0 3000 0 16.86% 2 60 2800 0 1.45% 3 90 2700 0 1.04% 4 150 2500 0 0.55%5 225 2250 0 0.48% 6 300 2000 0 0.33% 7 300 0 2000 0.31% 8 300 1000 10000.19% 9 150 1250 1250 0.27% 10 150 1250 0 0.58% 11 150 0 1250 1.41%

Example 22: Intensifier and Inhibitory Efficacy of CuI Nanoparticles in28% HCl

These experiments were performed using 28% HCl instead of 15% HCl andtested for corrosion inhibition in boiling HCl for 6 hours as describedin Example 19. The results demonstrate that the F1 formulation (ascorrosion inhibition intensifier) in combination withtrans-cinnamaldehyde as effective. F4 formulation which uses F1 alongwith PVP and NaI is also effective in 28% HCl.

TABLE 28 Corrosion of SS 304 balls at 100 C. for 6 hours in 28% HCl ppmppm, ppm Cu, propargyl trans- Sample source of CuI alcoholcinnamaldehyde % Loss 1 300 Cu as F1 2000 0 10.64% 2 300 Cu as F1 0 20001.26% 3 300 Cu as F1 1000 1000 2.98% 4 300 Cu as F4 0 0 2.97%

Example 23: Formulation with Two Corrosion Inhibitors and an Alkali Salt

Formulations were prepared using polyvinylpyrrolidone as a corrosioninhibitor along with another corrosion inhibitor in combination with aniodide salt. These formulations were tested for corrosion inhibition inboiling HCl for 6 hours as described in Example 19. The resultsdemonstrate that the combination of PVP with TCA (trans-cinnamaldehyde)and NaI provides improved corrosion protection.

TABLE 29 Corrosion of SS 304 balls at 100 C. for 6 hours in 15% HClSample ppm NaI ppm PVP ppm TCA % Loss 1 2000 0 8000 0.32% 2 2000 0 10000.74% 3 2000 3000 1000 0.07%

Example 24: Efficacy of CuI and NaI as Corrosion Inhibitor Intensifiers

NaI or CuI as F1 was combined with various corrosion inhibitors in 15%HCl and tested for corrosion inhibition as in Example 19. NaI and the F1formulation were both tested at equivalent iodide concentration. Theresults demonstrate that the F1 formulation has superior efficacy ascompared to NaI. Samples 1-3 demonstrate that the F1 formulation hassuperior inhibitory affects in the absence of a traditional corrosioninhibitor as compared to NaI. Samples 4-15 demonstrate that the F1formulation has superior inhibitory affects when combined with atraditional corrosion inhibitor as compared to NaI.

TABLE 30 Corrosion of SS 304 balls at 100 C. for 6 hours in 15% HCl ppmppm ppm ppm ppm ppm Sample F1 NaI PA TCA DDPC BAC % Loss 1 1000 0 0 0 00 1.06% 2 0 720 0 0 0 0 11.56% 3 0 0 0 0 0 0 49.39% 4 1000 0 2000 0 0 00.13% 5 0 720 2000 0 0 0 0.65% 6 0 0 2000 0 0 0 31.97% 7 1000 0 0 2000 00 0.19% 8 0 720 0 2000 0 0 0.41% 9 0 0 0 2000 0 0 45.85% 10 1000 0 0 02000 0 0.39% 11 0 720 0 0 2000 0 2.31% 12 0 0 0 0 2000 0 19.60% 13 10000 0 0 0 2000 0.36% 14 0 720 0 0 0 2000 1.16% 15 0 0 0 0 0 2000 58.47%

Example 25: Comparison of F1 with Mixtures of NaI and CuCl₂ and Mixturesof F1, NaI, and CuCl₂

CuCl₂, NaI, and CuI (as F1) were combined with a corrosion inhibitorblend consisting of PA and DDPC in 15% HCl and tested for corrosioninhibition as in Example 19, on 1018 low carbon steel balls (diameter5/16 inch or 0.79 cm). CuCl₂, NaI, and F1 were tested separately and asmixtures. The results demonstrate that the F1 formulation has superiorinhibition intensifier efficacy as compared to both NaI and CuCl₂ andmixtures of NaI and CuCl₂ for low carbon steel.

TABLE 31 Corrosion of 1018 low carbon steel balls at 100 C. for 6 hoursin 15% HCl ppm ppm ppm ppm ppm Sample F1 NaI CuCl₂ DDPC PA % Loss 1 10000 0 1000 1000 0.98% 2 667 333 0 1000 1000 9.57% 3 667 0 333 1000 10007.29% 4 333 667 0 1000 1000 6.19% 5 333 333 333 1000 1000 3.00% 6 333 0667 1000 1000 6.74% 7 0 1000 0 1000 1000 57.25% 8 0 667 333 1000 100011.35% 9 0 333 667 1000 1000 12.57% 10 0 0 1000 1000 1000 5.64%

Example 26: Efficacy of F1 Compared to NaI or CuCl (all at 1000 PPM) asCorrosion Intensifiers for Four Different Steels when Added to CorrosionInhibitors DDPC and PA

CuCl₂, NaI, or CuI as F1 was combined with a corrosion inhibitor blendconsisting of TCA and DDPC in 15% HCl and tested for corrosioninhibition as in Example 19, however, different metals were alsocompared. CuCl₂, NaI, and F1 were all tested at equivalent ppm of totalmaterial, thus NaI has more iodide than F1 and CuCl₂ has more copperthan F1. The results demonstrate that the F1 formulation has superiorefficacy as compared to both NaI and CuCl₂ for all four metalchemistries tested. Collectively, these results demonstrate that the F1formulation has superior inhibitory effects as intensifiers across awide variety of metals. Unless specifically mentioned, in allexperiments when balls were used for testing, the size of 1018 and S2steel were similar ( 5/16 inch or 0.79 cm) and the diameter of stainlesssteel 304 and steel E52100 balls used in the evaluation was similar (9/32 inch or 0.71 cm).

TABLE 32 Corrosion of various steel balls at 100 C. for 6 hours in 15%HCl ppm ppm ppm ppm ppm % Loss Sample F1 NaI CuCl₂ DDPC PA Metal (n = 2)1 1000 0 0 1000 1000 1018 0.32% 2 0 1000 0 1000 1000 6.88% 3 0 0 10001000 1000 0.82% 4 0 0 0 1000 1000 14.64% 5 0 0 0 0 0 58.55% 6 1000 0 01000 1000 304 0.08% 7 0 1000 0 1000 1000 0.10% 8 0 0 1000 1000 10000.48% 9 0 0 0 1000 1000 0.60% 10 0 0 0 0 0 29.36% 11 1000 0 0 1000 1000S2 1.00% 12 0 1000 0 1000 1000 4.00% 13 0 0 1000 1000 1000 2.64% 14 0 00 1000 1000 12.60% 15 0 0 0 0 0 55.47% 16 1000 0 0 1000 1000 E521000.19% 17 0 1000 0 1000 1000 1.45% 18 0 0 1000 1000 1000 0.80% 19 0 0 01000 1000 3.29% 20 0 0 0 0 0 79.01%

Example 27: Efficacy of F1 as Compared to NaI and Also to CuCl (Mixed atEquivalent Cu and I) for Four Different Steels when Added to InhibitorsComprising DDPC and TCA

CuCl₂, NaI, or CuI as F1 was combined with a corrosion inhibitor blendconsisting of TCA and DDPC in 15% HCl and tested for corrosioninhibition as in Example 19, however, different metals were alsocompared. CuCl₂, NaI, and F1 were all tested at equivalent ppm of copperand iodide. The results demonstrate that the F1 (CuI) formulation hassuperior efficacy as compared to when NaI and CuCl₂ are added atequivalent copper and iodide concentrations. The results alsodemonstrate that formulation F1 has superior pitting resistance.

TABLE 33 Corrosion of 1018 low carbon steel balls at 100 C. for 6 hoursin 15% HCl ppm ppm ppm ppm ppm F1 NaI CuCl2 DDPC TCA Metal % LossPitting 1 1000 0 0 1000 1000 1018 0.18% No 2 0 720 338 1000 1000 10180.58% Yes 3 500 0 0 1000 1000 1018 0.63% No 4 0 360 169 1000 1000 10180.81% Yes 5 1000 0 0 1000 1000 304 0.07% No 6 0 720 338 1000 1000 3040.09% No 7 500 0 0 1000 1000 304 0.16% No 8 0 360 169 1000 1000 3040.15% No 9 1000 0 0 1000 1000 S2 2.03% Yes 10 0 720 338 1000 1000 S21.51% Yes 11 500 0 0 1000 1000 S2 2.10% Yes 12 0 360 169 1000 1000 S21.00% Yes 13 1000 0 0 1000 1000 E52100 0.23% No 14 0 720 338 1000 1000E52100 0.23% No 15 500 0 0 1000 1000 E52100 0.34% No 16 0 360 169 10001000 E52100 0.37% No

Example 28: Compatibility of F1 formulation in Presence of CommonAcidizing Additives

F1 was combined with DDPC and TCA as in Example 26 and tested against1018 low carbon steel as in Example 25. Separately each of a variety ofcommon acidizing additives were tested along with F1 to see if anyadverse reaction (such as precipitation) or reduction of corrosioninhibition is observed. The materials were citric acid, acetic acid andsodium ascorbate (used as iron control agents), polyacrylamide andpolyacrylate (used as scale inhibitors), Sodium lauryl sulfate (SLS),isopropyl alcohol (IPA) and ethylene glycol (used for emulsionprevention of oil and acids) and calcium chloride (added to preventanhydrite precipitation). These were tested by separately adding theseto F1 and then testing the efficacy of the mixture on 1018 steel in 15%HCl for 6 hours at 100 C. The additives were 12,000 ppm citric acid,12,000 ppm acetic acid, 12,000 ppm sodium ascorbate, 10 wt % CaCl₂, 1000ppm polyacrylamide (MW=10,000), 1000 ppm polyacrylate (MW=1800), 2000ppm SLS, 2000 ppm isopropylalcohol, 2000 ppm ethylene glycol, and 2000ppm pentanol. None of these affected the corrosion inhibition efficacyof the F1 formulation.

Example 29: Efficacy of Tungsten Chloride and Manganese Chloride asCorrosion Inhibitor Intensifiers

WCl₆, MnCl₂, or NaI were combined as corrosion intensifier inhibitorswith DDPC and TCA and tested against 1018 low carbon steel as in Example25. The results demonstrate that WCl₆ and MnCl₂ also work as effectivecorrosion inhibitor intensifiers. One may also combine several of theseintensifiers in the same formulation.

TABLE 34 Corrosion of 1018 low carbon steel balls at 100 C. for 6 hoursin 15% HCl ppm ppm ppm ppm ppm ppm Sample TCA PA DDPC NaI WCl₆ MnCl₂ %Loss 1 1000 1000 25.72% 2 1000 1000 1000 5.80% 3 1000 1000 1000 2.53% 41000 1000 1000 17.07% 5 1000 1000 1000 1000 0.98

Example 30: Corrosion Inhibition Formulation with Derivative of PropagylAlcohol and Water Soluble Salt of Copper

Samples of various steels were tested as in Example 19 at 200 f (˜93 C)for 24 hours in 15% HCl. The formulations had either propagyl alcohol(PA), or a derivative of propagyl alcohol PM. PM is Korantin® PM(available from BASF, Germany) and is a propagyl alcohol alkoxylate.

TABLE 35 Corrosion of various steel balls at 200 F. for 24 hours in 15%HCl % % Loss Loss CuCl₂, PM, PA, TCA, DDPC, Low C. Steel St. SteelSample ppm ppm ppm ppm ppm 1018 304 1 500 2000 250 2.92% 7.26% 2 5001500 250 3.28% 12.99% 3 500 1000 250 3.39% 20.61% 4 500 1000 1000 2501.78% 6.78% 6 500 500 1000 250 2.20% 26.87% 7 500 2000 250 3.95% 30.07%9 500 1000 250 4.86% 85.10% 10 500 2000 250 1.42% 41.95%

The results show that superior results were obtained when all three TCA,DDPC and propargyl alcohol (or a derivative of propargyl alcohol) waspresent. For example result 4 is superior to result 1, where the totalamount of corrosion inhibitor is the same, but the latter has all thethree ingredients. Similarly sample 6 with all of the three inhibitorspresent is superior to sample 2 (both have similar concentration ofcorrosion inhibitors). Another experiment was done by varying thecomposition as shown in Table 36. The results show that in theformulations containing all three inhibitors, TCA helps to reducepitting on the surface as the surfaces after the test were shiny with noappearance of pits (e.g., compare sample 13 with 10). As seen in theseresults, one can lower the concentration of TCA and the cationicsurfactant and still get highly favorable results (compare samples 1, 4,7 and 10). Further the preferred corrosion inhibition formulation (e.g.,sample 10) had a higher concentration of propargyl alcohol (or apolymerizable material) as compared to the aldehyde and the cationicsurfactant

TABLE 36 Corrosion of low carbon steel balls (type 1018) at 200 F. for24 hours in 15% HCl CuCl2, PA, TCA, DDPC, Average Loss Surface Sampleppm ppm ppm ppm (n = 3) appearance 1 500 1000 1000 250 2.24% SHINTY 4500 2000 800 250 1.44% SHINTY 7 500 2000 500 250 1.68% SHINTY 10 5002000 250 250 1.60% SHINTY 13 500 2000 250 1.82% NOT SHINY

Table 37 shows that in a formulation containing PA, TCA and the DDPC, ifone were to remove DDPC, the loss in weight (or corrosion) increaseddramatically, thus the combination of a polymerizable material, analdehyde and a cationic surfactant is a highly synergistic corrosioninhibition formulation. In addition, when corrosion is measured at 200F, it shows that copper is not playing an important role and can beeliminated from the formulation for low carbon steels (compare samplesin Tables 37 and 38).

TABLE 37 Corrosion of low carbon steel (type 1018) balls at 200 F. for24 hours in 15% HCl CuCl2, PA, TCA, DDPC, Sample ppm ppm ppm ppm % Loss1 500 2000 250 250 1.54% 6 500 2000 250 125 0.49% 7 500 2000 250 032.98%

TABLE 37 Corrosion of low carbon steel (type 1018) balls at 200 F. for24 hours in 15% HCl Sample CuCl2 PA TCA DDPC % Loss Surface appearance15 0 2000 250 125 0.55% SHINY

In another experiment, steel balls (steel type 1018) were used andsubject to corrosion in different volumes of acid (15% HCl) at 200 F for24 hours. The flask shape and volume was same for all of theseexperiments. As shown in Table 38, when there was no inhibitor in theacid, the weight loss increased with increasing acid volume, since aconsiderable amount of acid gets consumed in reacting with the metal,and as the acid gets used up its concentration drops decreasing itsreactivity. When small amounts of acid are used, then the weight lossslows down or gets arrested as the acid concentration drops. The sameexperiment was carried out using 10 ml and 20 ml of the acid with PA,TCA and DDPC concentrations of 2000, 250 and 125 ppm respectively, asseen in Table 38, 10 ml of inhibited acid is sufficient to providereliable results since very little acid is consumed, and there is only alittle change in acid concentration over the experimentation period.

TABLE 38 Effect of acid volume on corrosion results Acid Acid (mL)inhibited? Wt Loss Notes 2.5 No 17% sample not fully submerged 5 No 34%10 No 60% 20 No 100%  10 Yes  1% 20 Yes  1%

Example 31: Corrosion Inhibition on Various Steels Used in Oil Field

In this experiment, several steels certified by American petroleuminstitute (API) were evaluated in 15% HCl. These steels were QT1000(Obtained from Quality Tubing, Houston, Tex.); and N80 and Cr13(obtained from CPCO Inc, Claremore, Okla.). For QT1000, coupons were cutfrom a flat steel stock in a thickness of 3/16 inch (0.48 cm) and a sizeof 1 cm by 1 cm. For others samples were cut from a pipe in a size of 1cm×1 cm. the thickness of Cr13 coupons was 3/16 inch and for N80 it was⅛ inch (0.32 cm). For 1018 steel and stainless steel 304, solid ballswere used in a size as discussed earlier. The acid volume was 10 ml.Each sample was put in a separate round bottom flask and a number ofthese were then placed in a thermally controlled liquid bath and eachflask fitted with a condenser system to avoid any loss of acid from theflasks. The weight loss results are shown in the Table 39. The corrosioninhibitor containing all three components, i.e., polymerizable monomer(propargyl alcohol (PA), transcinnamonaldehyde (TCA) and dodecylpyridinium chloride (DDPC) performed the best on all steels showing thelowest weight loss. Results are also shown when the monomeric component(PA) was not used corrosion (weight loss) went up, and the amount ofcorrosion was higher by more than a factor of 100 when none of theinhibitor components were added to the acid. These results also showthat use of 1018 or 304 stainless steels were good substitutes inprevious experiments to determine the compositions for corrosioninhibitors.

TABLE 39 Corrosion of various API steels and other steels 200 F. for 24hours in 15% HCl with corrosion inhibitor. Sample PA TCA DDPC Steel %Loss 1 2000 250 125 1018 Ball 0.51% 2 2000 250 125 1018 Ball 0.46% 32000 250 125 QT1000 0.31% 4 2000 250 125 QT1000 0.26% 5 2000 250 125 304Ball 0.09% 6 2000 250 125 304 Ball 0.10% 7 2000 250 125 CR13 0.46% 82000 250 125 CR13 0.47% 9 2000 250 125 S2Ball 3.04% 10 2000 250 125S2Ball 2.55% 11 2000 250 125 E52100 Ball 0.51% 12 2000 250 125 E52100Ball 0.43% 13 2000 250 125 N80 0.31% 14 2000 250 125 N80 0.32% 15 20002000 QT1000 1.19% 16 QT1000 34.86% 17 2000 2000 CR13 1.08% 18 CR1339.27% 19 2000 2000 N80 1.41% 20 N80 43.18%

Additional experiments were conducted on the API steels at 150° F. (66°C.) and 200° F. (93° C.). The concentrations of the three inhibitorcomponents in 15% HCL was the same as in the above table (Table 38) forexperiments at 200 F and was cut down to half for experiments at 150 F.The time period for both experiments was 24 hours.

Further experiments were done to test the formulation 2000:250:125(PA:TCA:DDPC by weight). 2 GPT addition was used at 150 F and 4 GPT at200 F. 2 GPT works very well at 150° F. but at 200° F. a conc of 4 GPTwas used. This suggests that at higher temperatures higherconcentrations of corrosion inhibitor will have to be used. API steelsas approximately 1 cm×1 cm squares with a measured thickness of 3/16inch for the QT and CR13 or 2/16 for the N80 were used; and for non APIsteels, spheres were used: All of these experiments were conducted induplicates using 15% HCL. At 4 GPT, the concentration of PA:TCA:DDPC is2000:250:125 ppm in the acid.

TABLE 40 Corrosion inhibition effect of CI concentration and temperatureon various API steels in 15% HCl Temp, Time, Conc of CI, Weight lossSteel F. hrs GPT* (lb/ft²) 1018 200 24 4 0.0310 304 200 24 4 0.0054 QT200 24 4 0.0056 CR13 200 24 4 0.0079 N80 200 24 4 0.0059 QT 150 24 20.0058 CR13 150 24 2 0.0052 N80 150 24 2 0.0057 QT 150 24 4 0.0054 CR13150 24 4 0.0048 N80 150 24 4 0.0048

Additionally the results for the volume-concentration testing are belowat 200 F for 24 hrs.

TABLE 41 Effect of acid amount on corrosion of 1018 steel balls in 15%HCl Acid Actives Actives Wt (mL) (mole) (ppm) Loss Notes 2.5 0 0 17%sample not fully submerged 5 0 0 34% 10 0 0 60% 20 0 0 100%  2.5 0.000082375 16% 4 gpt, sample not fully submerged 5 0.00016 2375 10% 4 gpt 100.00031 2375  1% 4 gpt 20 0.00062 2375  1% 4 gpt 10 0.00016 1187.5 63% 2gpt 20 0.00031 1187.5 100%  2 gpt

With no corrosion inhibitor, weight loss increases with increasing acidvolume, as more of the steel gets consumed.

Example 32: Evaluation of the Additional Corrosion Inhibitors

In this experiment in addition to the propargyl alcohol (PA)cinnamonaldeyde (TCA) and DDPC, other nitrogen containing corrosioninhibitors were also evaluated. These were quinolone (QO), quinaladine(QA), and nicotinic acid (NA). Although quinolone and quinaladine arewell known in the art and did perform well with respect to weight lossof the samples, they imparted blemishes and burrs on to the surface ofthe metal. samples with nicotinic acid or propagyl containing samplesalong with DDPC and TCA performed markedly similar in maintaining asuperior surface finish.

TABLE 42 Comparison of various corrosion inhibitor formulations in 15%HCl on 1018 steel at 200 F. for 24 hrs. Sam- ple QA QAA NA PA TCA DDPC %Loss Notes 1 59.16% Corroded 2 2000 250 125  1.12% Pristine Surface 32000 250 125  0.93% Blemished 4 2000 250 125  1.24% Blemished 5 2000 250125  0.89% Pristine Surface 6 2000 250  23.6% Corroded 7 2000 250  49.3%Corroded 8 2000 250  48.5% Corroded 9 2000 250  57.4% Corroded

Example 33: Iron Reduction

Various formulations were tested for their ability to reduce ferric ionsto ferrous ions. Various aqueous solutions was first prepared asdescribed Table-43 for each sample, and labeled as “Solution 1”, wherevarious “Solution 1” formulations are then added to the 15% HClcontaining ferric ions as shown in Table 44.

TABLE 43 Solution 1 Example PA1 1 2 3 4 5 6 7 8 9 10 11 Water, ml 100100 100 100 100 100 100 100 100 100 100 100 Sodium sulfite, g 20 20 20Potassium iodide, g 2.7 NH₄ ⁺ Thioglycolate, g 2.8 2.8 2.8 CuprousIodide (F1), g 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 Cuprous Chloride, g 1.6Ascorbic Acid, g 4.7 4.7 4.7 4.7 Sodium Ascorbate, g 5.3 SodiumThiosulfate, g 4.3 4.3 4.3

An aliquot of this “Solution 1” from Table 43 was combined with a ferricion containing acid as described in Table-44. After two minutes, thisfinal mixture was examined for visual color change. The ferric ionsolution is initially strongly colored and upon reduction becomescolorless.

TABLE 44 Final Mixture Example PA1 1 2 3 4 5 6 7 8 9 10 11 Solution 1.51.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1 (from Table 43), ml FeCl₃,g 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 HCl 15%, 100 100 100100 100 100 100 100 100 ml Corrosion 100 100 100 Inhibited Acid* CuCl₂•20.04 H₂O, g Ferric ion Yes Yes No No Yes Yes Yes No Yes Yes Yes Yesreduction in two minutes *In addition to 15% HCL these have 2,000 ppm ofPA, 250 ppm of TCA and 125 ppm of DDPC (see sample 2 in Table 42)

As shown in the above tables, functionalized cuprous iodide particles asdescribed in Example 1 (F1) were combined with several iron reducingformulations. It was found in all formulations the prepared CuIparticles were effective in reducing iron (samples 1, 2, 3, 5). Theadvantage of F1 is its superior dispersability in a CI formulation whichcan be added to the acids in the field. These effective formulationswere further combined with acid along with corrosion inhibitors (samples9, 10, 11). The corrosion inhibitor containing formulations were equallyeffective in demonstrating a complete reduction of ferric ions in lessthan 2 minutes. The corrosion inhibition of the formulations containingboth the corrosion inhibitors and the ferric ion reducing materials isdiscussed in Example 35 however, their ferric ion reduction propertiesare confirmed by seeing the results on samples 9, 10 and 11.Specifically, Sample 10 can be compared with Sample 2 of table 45; andsample 11 of the above table can be compared with sample 11 of Table 45,showing that these formulations provide both ferric ion reduction andgood corrosion protection.

Example 34: Ferric Ion Reduction with Different Copper Salts

In order to demonstrate the superiority of cuprous compounds for ironreduction, several copper containing formulations were made. Theseformulations comprised ascorbic acid and one of: cuprous iodide, cuprouschloride, or cupric chloride. All of these formulations were preparedusing 100 ml of water with 2.35 g of ascorbic acid along with the coppersalts. The copper content of all of these solutions was the same, e.g.,in the solution with CuI, 3.4 g of CuI as F1 was used. Then 1.5 ml ofthese solutions were taken (as in Example 33 and mixed with ferric ionsolution. The ferric ion solution was 100 ml of HCl and 0.4 g of FeCl₃.After the two solutions were mixed, the copper concentration in thesewas 154 ppm and ascorbic acid was 353 ppm. These formulations wereprepared with lower amount of ascorbic acid in order to better resolvedifferences in the kinetics of ferric ion reduction.

Maximum absorbance of the ferric chloride containing acid was recordedat 375 nm, and this wavelength was used to measure reduction of Fe(III)to Fe(II) over a ten minute time period. The results of this, shown inFIG. 2, demonstrate that cuprous materials are more effective thancupric salts and furthermore cuprous iodide is far better than thecuprous chloride.

Example 35: Testing of Corrosion Inhibition of Formulations ComprisingCorrosion Inhibitors and Iron Reducing Components

In order to determine whether the addition of ferric iron reducingadditives had an effect on acid corrosion three of the ferric ionreduction formulations were added to 15% HCl acid which containedcorrosion inhibitors. In the acid, the corrosion inhibitors were presentat 2000 ppm PA, 250 ppm TCA, and 125 ppm DDPC. The numbers below thevarious ingredients in Table 45 are concentrations in ppm by weight inthe acid composition. The effect of these additions is shown in Table-45on corrosion inhibition expressed as weight loss when treated in theinhibited acid at 200° F. for 24 hours.

Samples 1 and 7 do not provide ferric ion reduction ability, whilecompositions 2, 3, 8, 9, 11 and 12 provide corrosion protection as wellas ferric ion reduction. Sample 9 is similar to the sample PA1 inExample 33 in terms of ferric ion reduction but it has been added to thecorrosion inhibitor of Embodiment 3. Sample 7 shows that the addition ofthese sulfur compounds degrades the performance of the corrosioninhibitor when other additives such as CuI or copper and iodide sourcesare not used as compared to the use of ascorbic acid in sample 1.

TABLE 45 Corrosion of low carbon steel (type 1018) balls at 200 F. for24 hours in inhibited 15% HCl CuI Ascorbic Sodium Ammonium Sodium %Sample CuCl₂ KI (F1) Acid Sulfite Thioglycolate Thiosulfate wtLoss 1 7050.95% 2 512 705 1.40% 3 315 405 705 0.92% 7 3000 420 16.67% 8 512 3000420 3.55% 9 315 405 3000 420 2.78% 10 645 2.40% 11 512 645 1.90% 12 315405 645 1.23%

It will be understood that various modifications may be made to theembodiments disclosed herein. Hence the above description should not beconstrued as limiting, but merely as exemplifications of preferredembodiments. Those skilled in the art will envision other modificationsthat come within the scope and spirit of the claims appended hereto. Allpatent applications cited as priority (related applications) areexplicitly incorporated herein by reference in their entirety.

The invention claimed is:
 1. A method for providing an acid solutionthat contacts a metal with at least one of (i) reduction in corrosion ofsaid metal by said acid solution and (ii) reduction in the formation offerric ions in said solution, comprising adding to said acid solution acorrosion inhibiting additive comprising particles of a low watersolubility material whose surfaces are modified by a surfacefunctionalization agent with a molecular weight of at least
 60. 2. Themethod of claim 1, wherein the low water solubility material is copperiodide.
 3. The method of claim 1, wherein the size of the particles isless than about 1,000 nm.
 4. The method of claim 1, wherein thecorrosion inhibiting additive additionally comprises a compound of atleast one of Li, Na, K, V, Cu, Co, Mo, Ta, Sn, Bi, Mn and W.
 5. Themethod of claim 4, wherein the compound is selected from at least one ofLiI, KI and NaI.
 6. The method of claim 1, wherein the corrosioninhibiting additive additionally comprises a reducing agent.
 7. Themethod of claim 1, where the corrosion inhibiting additive furthercomprises at least one material selected from the following categories:(a) cationic surfactant; (b) phenylpropanoid, and (c) a materialselected from at least one of a monomeric material and a nitrogencontaining material.
 8. The method of claim 7, wherein the saidmonomeric material comprises an acetylenic or a vinyl compound; thephenylpropanoid comprises cinnamonaldehyde; the nitrogen containingmaterial is selected from quinolines, nicotinic acid, and PVP containingpolymer; and the cationic surfactant comprises a cation selected fromammonium, phosphonium, imidazolium, pyridinium, pyrrolidinium,pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, andtriazolium.
 9. The method of claim 8, wherein the acetylenic compound isselected from propargyl alcohol and its derivatives, thecinnamonaldehyde comprises trans-cinnamonaldehyde, and the cationicsurfactant has at least one alkyl chain with an average length of C12 toC15.
 10. The method of claim 9, wherein the corrosion inhibitingadditive additionally comprises a compound of at least one of Na, K, V,Co, Mo, Ta, Sn, Bi, Mn, W, Cu and I.
 11. The method of claim 10, whereinthe said low water solubility material comprises pre-formed particles ofCuI in a size less than about 1,000 nm.
 12. The method of claim 7,wherein the corrosion inhibiting additive additionally comprises areducing agent.
 13. A method for providing an acid solution thatcontacts a metal with at least one of (i) reduction in corrosion of saidmetal by said acid solution and (ii) reduction in the formation offerric ions in said solution, comprising adding to said solution acorrosion inhibiting additive comprising pre-formed particles of a lowwater solubility material in a size less than about 1000 nm.
 14. Themethod of claim 13, wherein the low water solubility material is copperiodide.
 15. The method of claim 13, wherein the corrosion inhibitingadditive additionally comprises at least one compound of Li, Na, K, V,Cu, Co, Mo, Ta, Sn, Bi, Mn and W.
 16. The method of claim 15, whereinthe compound is selected from at least one of LiI, KI and NaI.
 17. Themethod of claim 13, wherein the corrosion inhibiting additiveadditionally comprises a reducing agent.
 18. The method of claim 13,where the corrosion inhibiting additive further comprises at least onematerial selected from the following categories: (a) cationicsurfactant; (b) phenylpropanoid, and (c) a material selected from atleast one of a monomeric material and a nitrogen containing material.19. The method of claim 18, wherein the corrosion inhibiting additiveadditionally comprises at least one compound of Li, Na, K, V, Cu, Co,Mo, Ta, Sn, Bi, Mn and W.
 20. The method of claim 13, wherein the saidmetal is a ferrous metal or alloy.